b_asic/GUI/port_button.py

+
+import sys
+
+from PyQt5.QtWidgets import QPushButton, QMenu
+from PyQt5.QtCore import Qt, pyqtSignal
+
+class PortButton(QPushButton):
+    connectionRequested = pyqtSignal(QPushButton)
+    moved = pyqtSignal()
+    def __init__(self, name, operation, window, parent=None):
+        self.pressed = False
+        self.window = window
+        self.operation = operation
+        self.clicked = 0
+        super(PortButton, self).__init__(name, operation)
+
+    def contextMenuEvent(self, event):
+        menu = QMenu()
+        menu.addAction("Connect", lambda: self.connectionRequested.emit(self))
+        menu.exec_(self.cursor().pos())
+
+    def mousePressEvent(self, event):
+        
+        if event.button() == Qt.LeftButton:
+            self.clicked += 1
+            if self.clicked == 1:
+                self.setStyleSheet("background-color: grey")
+                self.pressed = True
+                self.window.pressed_ports.append(self)
+            elif self.clicked == 2:
+                self.setStyleSheet("background-color: white")
+                self.pressed = False                
+                self.clicked = 0
+                self.window.pressed_ports.remove(self)
+        super(PortButton, self).mousePressEvent(event)
+            
+    def mouseReleaseEvent(self, event):
+        super(PortButton, self).mouseReleaseEvent(event)
+

b_asic/GUI/utils.py

+from PyQt5.QtWidgets import QErrorMessage
+from traceback import format_exc
+
+def handle_error(fn):
+    def wrapper(self, *args, **kwargs):
+        try:
+            return fn(self, *args, **kwargs)
+        except Exception as e:
+            QErrorMessage(self._window).showMessage(f"Unexpected error: {format_exc()}")
+
+    return wrapper
+
+def decorate_class(decorator):
+    def decorate(cls):
+        for attr in cls.__dict__:
+            if callable(getattr(cls, attr)):
+                setattr(cls, attr, decorator(getattr(cls, attr)))
+        return cls
+    return decorate
\ No newline at end of file

b_asic/__init__.py

@@ -4,11 +4,9 @@ TODO: More info.
 """
 from b_asic.core_operations import *
 from b_asic.graph_component import *
-from b_asic.graph_id import *
 from b_asic.operation import *
-from b_asic.precedence_chart import *
 from b_asic.port import *
-from b_asic.schema import *
 from b_asic.signal_flow_graph import *
 from b_asic.signal import *
 from b_asic.simulation import *
+from b_asic.special_operations import *

b_asic/core_operations.py

@@ -4,43 +4,39 @@ TODO: More info.
 """
 
 from numbers import Number
-from typing import Any
+from typing import Optional
 from numpy import conjugate, sqrt, abs as np_abs
-from b_asic.port import InputPort, OutputPort
-from b_asic.graph_id import GraphIDType
+
+from b_asic.port import SignalSourceProvider, InputPort, OutputPort
 from b_asic.operation import AbstractOperation
 from b_asic.graph_component import Name, TypeName
 
 
-class Input(AbstractOperation):
-    """Input operation.
-    TODO: More info.
-    """
-
-    # TODO: Implement all functions.
-
-    @property
-    def type_name(self) -> TypeName:
-        return "in"
-
-
 class Constant(AbstractOperation):
     """Constant value operation.
     TODO: More info.
     """
 
     def __init__(self, value: Number = 0, name: Name = ""):
-        super().__init__(name)
+        super().__init__(input_count=0, output_count=1, name=name)
+        self.set_param("value", value)
 
-        self._output_ports = [OutputPort(0, self)]
-        self._parameters["value"] = value
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "c"
 
     def evaluate(self):
         return self.param("value")
 
     @property
-    def type_name(self) -> TypeName:
-        return "c"
+    def value(self) -> Number:
+        """Get the constant value of this operation."""
+        return self.param("value")
+
+    @value.setter
+    def value(self, value: Number) -> None:
+        """Set the constant value of this operation."""
+        return self.set_param("value", value)
 
 
 class Addition(AbstractOperation):
@@ -48,134 +44,86 @@ class Addition(AbstractOperation):
     TODO: More info.
     """
 
-    def __init__(self, source1: OutputPort = None, source2: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-
-        self._input_ports = [InputPort(0, self), InputPort(1, self)]
-        self._output_ports = [OutputPort(0, self)]
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, src1: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=2, output_count=1,
+                         name=name, input_sources=[src0, src1])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
-        if source2 is not None:
-            self._input_ports[1].connect(source2)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "add"
 
     def evaluate(self, a, b):
         return a + b
 
-    @property
-    def type_name(self) -> TypeName:
-        return "add"
-
 
 class Subtraction(AbstractOperation):
     """Binary subtraction operation.
     TODO: More info.
     """
 
-    def __init__(self, source1: OutputPort = None, source2: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self), InputPort(1, self)]
-        self._output_ports = [OutputPort(0, self)]
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, src1: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=2, output_count=1,
+                         name=name, input_sources=[src0, src1])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
-        if source2 is not None:
-            self._input_ports[1].connect(source2)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "sub"
 
     def evaluate(self, a, b):
         return a - b
 
-    @property
-    def type_name(self) -> TypeName:
-        return "sub"
-
 
 class Multiplication(AbstractOperation):
     """Binary multiplication operation.
     TODO: More info.
     """
 
-    def __init__(self, source1: OutputPort = None, source2: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self), InputPort(1, self)]
-        self._output_ports = [OutputPort(0, self)]
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, src1: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=2, output_count=1,
+                         name=name, input_sources=[src0, src1])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
-        if source2 is not None:
-            self._input_ports[1].connect(source2)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "mul"
 
     def evaluate(self, a, b):
         return a * b
 
-    @property
-    def type_name(self) -> TypeName:
-        return "mul"
-
 
 class Division(AbstractOperation):
     """Binary division operation.
     TODO: More info.
     """
 
-    def __init__(self, source1: OutputPort = None, source2: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self), InputPort(1, self)]
-        self._output_ports = [OutputPort(0, self)]
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, src1: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=2, output_count=1,
+                         name=name, input_sources=[src0, src1])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
-        if source2 is not None:
-            self._input_ports[1].connect(source2)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "div"
 
     def evaluate(self, a, b):
         return a / b
 
-    @property
-    def type_name(self) -> TypeName:
-        return "div"
 
-
-class SquareRoot(AbstractOperation):
-    """Unary square root operation.
-    TODO: More info.
-    """
-
-    def __init__(self, source1: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self)]
-        self._output_ports = [OutputPort(0, self)]
-
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
-
-    def evaluate(self, a):
-        return sqrt((complex)(a))
-
-    @property
-    def type_name(self) -> TypeName:
-        return "sqrt"
-
-
-class ComplexConjugate(AbstractOperation):
-    """Unary complex conjugate operation.
+class Min(AbstractOperation):
+    """Binary min operation.
     TODO: More info.
     """
 
-    def __init__(self, source1: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self)]
-        self._output_ports = [OutputPort(0, self)]
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, src1: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=2, output_count=1,
+                         name=name, input_sources=[src0, src1])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
-
-    def evaluate(self, a):
-        return conjugate(a)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "min"
 
-    @property
-    def type_name(self) -> TypeName:
-        return "conj"
+    def evaluate(self, a, b):
+        assert not isinstance(a, complex) and not isinstance(b, complex), \
+            ("core_operations.Min does not support complex numbers.")
+        return a if a < b else b
 
 
 class Max(AbstractOperation):
@@ -183,155 +131,112 @@ class Max(AbstractOperation):
     TODO: More info.
     """
 
-    def __init__(self, source1: OutputPort = None, source2: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self), InputPort(1, self)]
-        self._output_ports = [OutputPort(0, self)]
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, src1: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=2, output_count=1,
+                         name=name, input_sources=[src0, src1])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
-        if source2 is not None:
-            self._input_ports[1].connect(source2)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "max"
 
     def evaluate(self, a, b):
         assert not isinstance(a, complex) and not isinstance(b, complex), \
             ("core_operations.Max does not support complex numbers.")
         return a if a > b else b
 
-    @property
-    def type_name(self) -> TypeName:
-        return "max"
-
-
-class Min(AbstractOperation):
-    """Binary min operation.
-    TODO: More info.
-    """
-
-    def __init__(self, source1: OutputPort = None, source2: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self), InputPort(1, self)]
-        self._output_ports = [OutputPort(0, self)]
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
-        if source2 is not None:
-            self._input_ports[1].connect(source2)
-
-    def evaluate(self, a, b):
-        assert not isinstance(a, complex) and not isinstance(b, complex), \
-            ("core_operations.Min does not support complex numbers.")
-        return a if a < b else b
-
-    @property
-    def type_name(self) -> TypeName:
-        return "min"
-
-
-class Absolute(AbstractOperation):
-    """Unary absolute value operation.
+class SquareRoot(AbstractOperation):
+    """Unary square root operation.
     TODO: More info.
     """
 
-    def __init__(self, source1: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self)]
-        self._output_ports = [OutputPort(0, self)]
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=1, output_count=1,
+                         name=name, input_sources=[src0])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "sqrt"
 
     def evaluate(self, a):
-        return np_abs(a)
+        return sqrt(complex(a))
 
-    @property
-    def type_name(self) -> TypeName:
-        return "abs"
 
-
-class ConstantMultiplication(AbstractOperation):
-    """Unary constant multiplication operation.
+class ComplexConjugate(AbstractOperation):
+    """Unary complex conjugate operation.
     TODO: More info.
     """
 
-    def __init__(self, coefficient: Number, source1: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self)]
-        self._output_ports = [OutputPort(0, self)]
-        self._parameters["coefficient"] = coefficient
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=1, output_count=1,
+                         name=name, input_sources=[src0])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "conj"
 
     def evaluate(self, a):
-        return a * self.param("coefficient")
-
-    @property
-    def type_name(self) -> TypeName:
-        return "cmul"
+        return conjugate(a)
 
 
-class ConstantAddition(AbstractOperation):
-    """Unary constant addition operation.
+class Absolute(AbstractOperation):
+    """Unary absolute value operation.
     TODO: More info.
     """
 
-    def __init__(self, coefficient: Number, source1: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self)]
-        self._output_ports = [OutputPort(0, self)]
-        self._parameters["coefficient"] = coefficient
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=1, output_count=1,
+                         name=name, input_sources=[src0])
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "abs"
 
     def evaluate(self, a):
-        return a + self.param("coefficient")
-
-    @property
-    def type_name(self) -> TypeName:
-        return "cadd"
+        return np_abs(a)
 
 
-class ConstantSubtraction(AbstractOperation):
-    """Unary constant subtraction operation.
+class ConstantMultiplication(AbstractOperation):
+    """Unary constant multiplication operation.
     TODO: More info.
     """
 
-    def __init__(self, coefficient: Number, source1: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self)]
-        self._output_ports = [OutputPort(0, self)]
-        self._parameters["coefficient"] = coefficient
+    def __init__(self, value: Number = 0, src0: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=1, output_count=1,
+                         name=name, input_sources=[src0])
+        self.set_param("value", value)
 
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "cmul"
 
     def evaluate(self, a):
-        return a - self.param("coefficient")
+        return a * self.param("value")
 
     @property
-    def type_name(self) -> TypeName:
-        return "csub"
+    def value(self) -> Number:
+        """Get the constant value of this operation."""
+        return self.param("value")
+
+    @value.setter
+    def value(self, value: Number) -> None:
+        """Set the constant value of this operation."""
+        return self.set_param("value", value)
 
 
-class ConstantDivision(AbstractOperation):
-    """Unary constant division operation.
+class Butterfly(AbstractOperation):
+    """Butterfly operation that returns two outputs.
+    The first output is a + b and the second output is a - b.
     TODO: More info.
     """
 
-    def __init__(self, coefficient: Number, source1: OutputPort = None, name: Name = ""):
-        super().__init__(name)
-        self._input_ports = [InputPort(0, self)]
-        self._output_ports = [OutputPort(0, self)]
-        self._parameters["coefficient"] = coefficient
-
-        if source1 is not None:
-            self._input_ports[0].connect(source1)
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, src1: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=2, output_count=2,
+                         name=name, input_sources=[src0, src1])
 
-    def evaluate(self, a):
-        return a / self.param("coefficient")
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "bfly"
 
-    @property
-    def type_name(self) -> TypeName:
-        return "cdiv"
+    def evaluate(self, a, b):
+        return a + b, a - b

b_asic/graph_component.py

@@ -4,10 +4,15 @@ TODO: More info.
 """
 
 from abc import ABC, abstractmethod
-from typing import NewType
+from collections import deque
+from copy import copy, deepcopy
+from typing import NewType, Any, Dict, Mapping, Iterable, Generator
+
 
 Name = NewType("Name", str)
 TypeName = NewType("TypeName", str)
+GraphID = NewType("GraphID", str)
+GraphIDNumber = NewType("GraphIDNumber", int)
 
 
 class GraphComponent(ABC):
@@ -15,35 +20,90 @@ class GraphComponent(ABC):
     TODO: More info.
     """
 
-    @property
+    @classmethod
     @abstractmethod
-    def type_name(self) -> TypeName:
-        """Return the type name of the graph component"""
+    def type_name(cls) -> TypeName:
+        """Get the type name of this graph component"""
         raise NotImplementedError
 
     @property
     @abstractmethod
     def name(self) -> Name:
-        """Return the name of the graph component."""
+        """Get the name of this graph component."""
         raise NotImplementedError
 
     @name.setter
     @abstractmethod
     def name(self, name: Name) -> None:
-        """Set the name of the graph component to the entered name."""
+        """Set the name of this graph component to the given name."""
+        raise NotImplementedError
+
+    @property
+    @abstractmethod
+    def graph_id(self) -> GraphID:
+        """Get the graph id of this graph component."""
+        raise NotImplementedError
+
+    @graph_id.setter
+    @abstractmethod
+    def graph_id(self, graph_id: GraphID) -> None:
+        """Set the graph id of this graph component to the given id.
+        Note that this id will be ignored if this component is used to create a new graph,
+        and that a new local id will be generated for it instead."""
+        raise NotImplementedError
+
+    @property
+    @abstractmethod
+    def params(self) -> Mapping[str, Any]:
+        """Get a dictionary of all parameter values."""
+        raise NotImplementedError
+
+    @abstractmethod
+    def param(self, name: str) -> Any:
+        """Get the value of a parameter.
+        Returns None if the parameter is not defined.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def set_param(self, name: str, value: Any) -> None:
+        """Set the value of a parameter.
+        Adds the parameter if it is not already defined.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def copy_component(self, *args, **kwargs) -> "GraphComponent":
+        """Get a new instance of this graph component type with the same name, id and parameters."""
+        raise NotImplementedError
+
+    @property
+    @abstractmethod
+    def neighbors(self) -> Iterable["GraphComponent"]:
+        """Get all components that are directly connected to this operation."""
+        raise NotImplementedError
+
+    @abstractmethod
+    def traverse(self) -> Generator["GraphComponent", None, None]:
+        """Get a generator that recursively iterates through all components that are connected to this operation,
+        as well as the ones that they are connected to.
+        """
         raise NotImplementedError
 
 
 class AbstractGraphComponent(GraphComponent):
     """Abstract Graph Component class which is a component of a signal flow graph.
-
     TODO: More info.
     """
 
     _name: Name
+    _graph_id: GraphID
+    _parameters: Dict[str, Any]
 
     def __init__(self, name: Name = ""):
         self._name = name
+        self._graph_id = ""
+        self._parameters = {}
 
     @property
     def name(self) -> Name:
@@ -52,3 +112,41 @@ class AbstractGraphComponent(GraphComponent):
     @name.setter
     def name(self, name: Name) -> None:
         self._name = name
+
+    @property
+    def graph_id(self) -> GraphID:
+        return self._graph_id
+
+    @graph_id.setter
+    def graph_id(self, graph_id: GraphID) -> None:
+        self._graph_id = graph_id
+
+    @property
+    def params(self) -> Mapping[str, Any]:
+        return self._parameters.copy()
+
+    def param(self, name: str) -> Any:
+        return self._parameters.get(name)
+
+    def set_param(self, name: str, value: Any) -> None:
+        self._parameters[name] = value
+
+    def copy_component(self, *args, **kwargs) -> GraphComponent:
+        new_component = self.__class__(*args, **kwargs)
+        new_component.name = copy(self.name)
+        new_component.graph_id = copy(self.graph_id)
+        for name, value in self.params.items():
+            new_component.set_param(copy(name), deepcopy(value))  # pylint: disable=no-member
+        return new_component
+
+    def traverse(self) -> Generator[GraphComponent, None, None]:
+        # Breadth first search.
+        visited = {self}
+        fontier = deque([self])
+        while fontier:
+            component = fontier.popleft()
+            yield component
+            for neighbor in component.neighbors:
+                if neighbor not in visited:
+                    visited.add(neighbor)
+                    fontier.append(neighbor)

b_asic/graph_id.py

-"""@package docstring
-B-ASIC Graph ID module for handling IDs of different objects in a graph.
-TODO: More info
-"""
-
-from collections import defaultdict
-from typing import NewType, DefaultDict
-
-GraphID = NewType("GraphID", str)
-GraphIDType = NewType("GraphIDType", str)
-GraphIDNumber = NewType("GraphIDNumber", int)
-
-
-class GraphIDGenerator:
-    """A class that generates Graph IDs for objects."""
-
-    _next_id_number: DefaultDict[GraphIDType, GraphIDNumber]
-
-    def __init__(self):
-        self._next_id_number = defaultdict(lambda: 1)       # Initalises every key element to 1
-
-    def get_next_id(self, graph_id_type: GraphIDType) -> GraphID:
-        """Return the next graph id for a certain graph id type."""
-        graph_id = graph_id_type + str(self._next_id_number[graph_id_type])
-        self._next_id_number[graph_id_type] += 1            # Increase the current id number
-        return graph_id

b_asic/operation.py

@@ -3,93 +3,187 @@ B-ASIC Operation Module.
 TODO: More info.
 """
 
+import collections
+
 from abc import abstractmethod
 from numbers import Number
-from typing import List, Dict, Optional, Any, Set, TYPE_CHECKING
-from collections import deque
+from typing import NewType, List, Sequence, Iterable, Mapping, MutableMapping, Optional, Any, Set, Union
+from math import trunc
 
 from b_asic.graph_component import GraphComponent, AbstractGraphComponent, Name
-from b_asic.simulation import SimulationState, OperationState
+from b_asic.port import SignalSourceProvider, InputPort, OutputPort
 from b_asic.signal import Signal
 
-if TYPE_CHECKING:
-    from b_asic.port import InputPort, OutputPort
+OutputKey = NewType("OutputKey", str)
+OutputMap = Mapping[OutputKey, Optional[Number]]
+MutableOutputMap = MutableMapping[OutputKey, Optional[Number]]
+RegisterMap = Mapping[OutputKey, Number]
+MutableRegisterMap = MutableMapping[OutputKey, Number]
 
 
-class Operation(GraphComponent):
+class Operation(GraphComponent, SignalSourceProvider):
     """Operation interface.
     TODO: More info.
     """
 
     @abstractmethod
-    def inputs(self) -> "List[InputPort]":
-        """Get a list of all input ports."""
+    def __add__(self, src: Union[SignalSourceProvider, Number]) -> "Addition":
+        """Overloads the addition operator to make it return a new Addition operation
+        object that is connected to the self and other objects.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def __radd__(self, src: Union[SignalSourceProvider, Number]) -> "Addition":
+        """Overloads the addition operator to make it return a new Addition operation
+        object that is connected to the self and other objects.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def __sub__(self, src: Union[SignalSourceProvider, Number]) -> "Subtraction":
+        """Overloads the subtraction operator to make it return a new Subtraction operation
+        object that is connected to the self and other objects.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def __rsub__(self, src: Union[SignalSourceProvider, Number]) -> "Subtraction":
+        """Overloads the subtraction operator to make it return a new Subtraction operation
+        object that is connected to the self and other objects.
+        """
         raise NotImplementedError
 
     @abstractmethod
-    def outputs(self) -> "List[OutputPort]":
-        """Get a list of all output ports."""
+    def __mul__(self, src: Union[SignalSourceProvider, Number]) -> "Union[Multiplication, ConstantMultiplication]":
+        """Overloads the multiplication operator to make it return a new Multiplication operation
+        object that is connected to the self and other objects. If other is a number then
+        returns a ConstantMultiplication operation object instead.
+        """
         raise NotImplementedError
 
+    @abstractmethod
+    def __rmul__(self, src: Union[SignalSourceProvider, Number]) -> "Union[Multiplication, ConstantMultiplication]":
+        """Overloads the multiplication operator to make it return a new Multiplication operation
+        object that is connected to the self and other objects. If other is a number then
+        returns a ConstantMultiplication operation object instead.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def __truediv__(self, src: Union[SignalSourceProvider, Number]) -> "Division":
+        """Overloads the division operator to make it return a new Division operation
+        object that is connected to the self and other objects.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def __rtruediv__(self, src: Union[SignalSourceProvider, Number]) -> "Division":
+        """Overloads the division operator to make it return a new Division operation
+        object that is connected to the self and other objects.
+        """
+        raise NotImplementedError
+
+    @property
     @abstractmethod
     def input_count(self) -> int:
         """Get the number of input ports."""
         raise NotImplementedError
 
+    @property
     @abstractmethod
     def output_count(self) -> int:
         """Get the number of output ports."""
         raise NotImplementedError
 
     @abstractmethod
-    def input(self, i: int) -> "InputPort":
-        """Get the input port at index i."""
+    def input(self, index: int) -> InputPort:
+        """Get the input port at the given index."""
+        raise NotImplementedError
+
+    @abstractmethod
+    def output(self, index: int) -> OutputPort:
+        """Get the output port at the given index."""
+        raise NotImplementedError
+
+    @property
+    @abstractmethod
+    def inputs(self) -> Sequence[InputPort]:
+        """Get all input ports."""
+        raise NotImplementedError
+
+    @property
+    @abstractmethod
+    def outputs(self) -> Sequence[OutputPort]:
+        """Get all output ports."""
+        raise NotImplementedError
+
+    @property
+    @abstractmethod
+    def input_signals(self) -> Iterable[Signal]:
+        """Get all the signals that are connected to this operation's input ports,
+        in no particular order.
+        """
+        raise NotImplementedError
+
+    @property
+    @abstractmethod
+    def output_signals(self) -> Iterable[Signal]:
+        """Get all the signals that are connected to this operation's output ports,
+        in no particular order.
+        """
         raise NotImplementedError
 
     @abstractmethod
-    def output(self, i: int) -> "OutputPort":
-        """Get the output port at index i."""
+    def key(self, index: int, prefix: str = "") -> OutputKey:
+        """Get the key used to access the output of a certain output of this operation
+        from the output parameter passed to current_output(s) or evaluate_output(s).
+        """
         raise NotImplementedError
 
     @abstractmethod
-    def params(self) -> Dict[str, Optional[Any]]:
-        """Get a dictionary of all parameter values."""
+    def current_output(self, index: int, registers: Optional[RegisterMap] = None, prefix: str = "") -> Optional[Number]:
+        """Get the current output at the given index of this operation, if available.
+        The registers parameter will be used for lookup.
+        The prefix parameter will be used as a prefix for the key string when looking for registers.
+        See also: current_outputs, evaluate_output, evaluate_outputs.
+        """
         raise NotImplementedError
 
     @abstractmethod
-    def param(self, name: str) -> Optional[Any]:
-        """Get the value of a parameter.
-        Returns None if the parameter is not defined.
+    def evaluate_output(self, index: int, input_values: Sequence[Number], results: Optional[MutableOutputMap] = None, registers: Optional[MutableRegisterMap] = None, prefix: str = "") -> Number:
+        """Evaluate the output at the given index of this operation with the given input values.
+        The results parameter will be used to store any results (including intermediate results) for caching.
+        The registers parameter will be used to get the current value of any intermediate registers that are encountered, and be updated with their new values.
+        The prefix parameter will be used as a prefix for the key string when storing results/registers.
+        See also: evaluate_outputs, current_output, current_outputs.
         """
         raise NotImplementedError
 
     @abstractmethod
-    def set_param(self, name: str, value: Any) -> None:
-        """Set the value of a parameter.
-        The parameter must be defined.
+    def current_outputs(self, registers: Optional[RegisterMap] = None, prefix: str = "") -> Sequence[Optional[Number]]:
+        """Get all current outputs of this operation, if available.
+        See current_output for more information.
         """
         raise NotImplementedError
 
     @abstractmethod
-    def evaluate_outputs(self, state: "SimulationState") -> List[Number]:
-        """Simulate the circuit until its iteration count matches that of the simulation state,
-        then return the resulting output vector.
+    def evaluate_outputs(self, input_values: Sequence[Number], results: Optional[MutableOutputMap] = None, registers: Optional[MutableRegisterMap] = None, prefix: str = "") -> Sequence[Number]:
+        """Evaluate all outputs of this operation given the input values.
+        See evaluate_output for more information.
         """
         raise NotImplementedError
 
     @abstractmethod
-    def split(self) -> "List[Operation]":
+    def split(self) -> Iterable["Operation"]:
         """Split the operation into multiple operations.
         If splitting is not possible, this may return a list containing only the operation itself.
         """
         raise NotImplementedError
 
-    @property
     @abstractmethod
-    def neighbors(self) -> "List[Operation]":
-        """Return all operations that are connected by signals to this operation.
-        If no neighbors are found, this returns an empty list.
-        """
+    def inputs_required_for_output(self, output_index: int) -> Iterable[int]:
+        """Get the input indices of all inputs in this operation whose values are required in order to evalueate the output at the given output index."""
         raise NotImplementedError
 
 
@@ -98,171 +192,212 @@ class AbstractOperation(Operation, AbstractGraphComponent):
     TODO: More info.
     """
 
-    _input_ports: List["InputPort"]
-    _output_ports: List["OutputPort"]
-    _parameters: Dict[str, Optional[Any]]
+    _input_ports: List[InputPort]
+    _output_ports: List[OutputPort]
 
-    def __init__(self, name: Name = ""):
+    def __init__(self, input_count: int, output_count: int, name: Name = "", input_sources: Optional[Sequence[Optional[SignalSourceProvider]]] = None):
         super().__init__(name)
-        self._input_ports = []
-        self._output_ports = []
-        self._parameters = {}
+
+        self._input_ports = [InputPort(self, i) for i in range(input_count)]
+        self._output_ports = [OutputPort(self, i) for i in range(output_count)]
+
+        # Connect given input sources, if any.
+        if input_sources is not None:
+            source_count = len(input_sources)
+            if source_count != input_count:
+                raise ValueError(
+                    f"Wrong number of input sources supplied to Operation (expected {input_count}, got {source_count})")
+            for i, src in enumerate(input_sources):
+                if src is not None:
+                    self._input_ports[i].connect(src.source)
 
     @abstractmethod
     def evaluate(self, *inputs) -> Any:  # pylint: disable=arguments-differ
-        """Evaluate the operation and generate a list of output values given a
-        list of input values.
-        """
+        """Evaluate the operation and generate a list of output values given a list of input values."""
         raise NotImplementedError
 
-    def inputs(self) -> List["InputPort"]:
-        return self._input_ports.copy()
+    def __add__(self, src: Union[SignalSourceProvider, Number]) -> "Addition":
+        # Import here to avoid circular imports.
+        from b_asic.core_operations import Constant, Addition
+        return Addition(self, Constant(src) if isinstance(src, Number) else src)
+
+    def __radd__(self, src: Union[SignalSourceProvider, Number]) -> "Addition":
+        # Import here to avoid circular imports.
+        from b_asic.core_operations import Constant, Addition
+        return Addition(Constant(src) if isinstance(src, Number) else src, self)
+
+    def __sub__(self, src: Union[SignalSourceProvider, Number]) -> "Subtraction":
+        # Import here to avoid circular imports.
+        from b_asic.core_operations import Constant, Subtraction
+        return Subtraction(self, Constant(src) if isinstance(src, Number) else src)
+
+    def __rsub__(self, src: Union[SignalSourceProvider, Number]) -> "Subtraction":
+        # Import here to avoid circular imports.
+        from b_asic.core_operations import Constant, Subtraction
+        return Subtraction(Constant(src) if isinstance(src, Number) else src, self)
+
+    def __mul__(self, src: Union[SignalSourceProvider, Number]) -> "Union[Multiplication, ConstantMultiplication]":
+        # Import here to avoid circular imports.
+        from b_asic.core_operations import Multiplication, ConstantMultiplication
+        return ConstantMultiplication(src, self) if isinstance(src, Number) else Multiplication(self, src)
 
-    def outputs(self) -> List["OutputPort"]:
-        return self._output_ports.copy()
+    def __rmul__(self, src: Union[SignalSourceProvider, Number]) -> "Union[Multiplication, ConstantMultiplication]":
+        # Import here to avoid circular imports.
+        from b_asic.core_operations import Multiplication, ConstantMultiplication
+        return ConstantMultiplication(src, self) if isinstance(src, Number) else Multiplication(src, self)
 
+    def __truediv__(self, src: Union[SignalSourceProvider, Number]) -> "Division":
+        # Import here to avoid circular imports.
+        from b_asic.core_operations import Constant, Division
+        return Division(self, Constant(src) if isinstance(src, Number) else src)
+
+    def __rtruediv__(self, src: Union[SignalSourceProvider, Number]) -> "Division":
+        # Import here to avoid circular imports.
+        from b_asic.core_operations import Constant, Division
+        return Division(Constant(src) if isinstance(src, Number) else src, self)
+
+    @property
     def input_count(self) -> int:
         return len(self._input_ports)
 
+    @property
     def output_count(self) -> int:
         return len(self._output_ports)
 
-    def input(self, i: int) -> "InputPort":
-        return self._input_ports[i]
-
-    def output(self, i: int) -> "OutputPort":
-        return self._output_ports[i]
-
-    def params(self) -> Dict[str, Optional[Any]]:
-        return self._parameters.copy()
-
-    def param(self, name: str) -> Optional[Any]:
-        return self._parameters.get(name)
-
-    def set_param(self, name: str, value: Any) -> None:
-        assert name in self._parameters  # TODO: Error message.
-        self._parameters[name] = value
-
-    def evaluate_outputs(self, state: SimulationState) -> List[Number]:
-        # TODO: Check implementation.
-        input_count: int = self.input_count()
-        output_count: int = self.output_count()
-        assert input_count == len(self._input_ports)  # TODO: Error message.
-        assert output_count == len(self._output_ports)  # TODO: Error message.
-
-        self_state: OperationState = state.operation_states[self]
-
-        while self_state.iteration < state.iteration:
-            input_values: List[Number] = [0] * input_count
-            for i in range(input_count):
-                source: Signal = self._input_ports[i].signal
-                input_values[i] = source.operation.evaluate_outputs(state)[
-                    source.port_index]
-
-            self_state.output_values = self.evaluate(input_values)
-            # TODO: Error message.
-            assert len(self_state.output_values) == output_count
-            self_state.iteration += 1
-            for i in range(output_count):
-                for signal in self._output_ports[i].signals():
-                    destination: Signal = signal.destination
-                    destination.evaluate_outputs(state)
-
-        return self_state.output_values
-
-    def split(self) -> List[Operation]:
-        # TODO: Check implementation.
-        results = self.evaluate(self._input_ports)
-        if all(isinstance(e, Operation) for e in results):
-            return results
-        return [self]
+    def input(self, index: int) -> InputPort:
+        return self._input_ports[index]
+
+    def output(self, index: int) -> OutputPort:
+        return self._output_ports[index]
 
     @property
-    def neighbors(self) -> List[Operation]:
-        neighbors: List[Operation] = []
-        for port in self._input_ports:
-            for signal in port.signals:
-                neighbors.append(signal.source.operation)
-
-        for port in self._output_ports:
-            for signal in port.signals:
-                neighbors.append(signal.destination.operation)
-
-        return neighbors
-
-    def traverse(self) -> Operation:
-        """Traverse the operation tree and return a generator with start point in the operation."""
-        return self._breadth_first_search()
-
-    def _breadth_first_search(self) -> Operation:
-        """Use breadth first search to traverse the operation tree."""
-        visited: Set[Operation] = {self}
-        queue = deque([self])
-        while queue:
-            operation = queue.popleft()
-            yield operation
-            for n_operation in operation.neighbors:
-                if n_operation not in visited:
-                    visited.add(n_operation)
-                    queue.append(n_operation)
-
-    def __add__(self, other):
-        """Overloads the addition operator to make it return a new Addition operation
-        object that is connected to the self and other objects. If other is a number then
-        returns a ConstantAddition operation object instead.
-        """
-        # Import here to avoid circular imports.
-        from b_asic.core_operations import Addition, ConstantAddition
+    def inputs(self) -> Sequence[InputPort]:
+        return self._input_ports
 
-        if isinstance(other, Operation):
-            return Addition(self.output(0), other.output(0))
-        elif isinstance(other, Number):
-            return ConstantAddition(other, self.output(0))
-        else:
-            raise TypeError("Other type is not an Operation or a Number.")
+    @property
+    def outputs(self) -> Sequence[OutputPort]:
+        return self._output_ports
 
-    def __sub__(self, other):
-        """Overloads the subtraction operator to make it return a new Subtraction operation
-        object that is connected to the self and other objects. If other is a number then
-        returns a ConstantSubtraction operation object instead.
-        """
-        # Import here to avoid circular imports.
-        from b_asic.core_operations import Subtraction, ConstantSubtraction
+    @property
+    def input_signals(self) -> Iterable[Signal]:
+        result = []
+        for p in self.inputs:
+            for s in p.signals:
+                result.append(s)
+        return result
 
-        if isinstance(other, Operation):
-            return Subtraction(self.output(0), other.output(0))
-        elif isinstance(other, Number):
-            return ConstantSubtraction(other, self.output(0))
+    @property
+    def output_signals(self) -> Iterable[Signal]:
+        result = []
+        for p in self.outputs:
+            for s in p.signals:
+                result.append(s)
+        return result
+
+    def key(self, index: int, prefix: str = "") -> OutputKey:
+        key = prefix
+        if self.output_count != 1:
+            if key:
+                key += "."
+            key += str(index)
+        elif not key:
+            key = str(index)
+        return key
+
+    def current_output(self, index: int, registers: Optional[RegisterMap] = None, prefix: str = "") -> Optional[Number]:
+        return None
+
+    def evaluate_output(self, index: int, input_values: Sequence[Number], results: Optional[MutableOutputMap] = None, registers: Optional[MutableRegisterMap] = None, prefix: str = "") -> Number:
+        if index < 0 or index >= self.output_count:
+            raise IndexError(
+                f"Output index out of range (expected 0-{self.output_count - 1}, got {index})")
+        if len(input_values) != self.input_count:
+            raise ValueError(
+                f"Wrong number of input values supplied to operation (expected {self.input_count}, got {len(input_values)})")
+        if results is None:
+            results = {}
+        if registers is None:
+            registers = {}
+
+        values = self.evaluate(*self.truncate_inputs(input_values))
+        if isinstance(values, collections.abc.Sequence):
+            if len(values) != self.output_count:
+                raise RuntimeError(
+                    f"Operation evaluated to incorrect number of outputs (expected {self.output_count}, got {len(values)})")
+        elif isinstance(values, Number):
+            if self.output_count != 1:
+                raise RuntimeError(
+                    f"Operation evaluated to incorrect number of outputs (expected {self.output_count}, got 1)")
+            values = (values,)
         else:
-            raise TypeError("Other type is not an Operation or a Number.")
+            raise RuntimeError(
+                f"Operation evaluated to invalid type (expected Sequence/Number, got {values.__class__.__name__})")
 
-    def __mul__(self, other):
-        """Overloads the multiplication operator to make it return a new Multiplication operation
-        object that is connected to the self and other objects. If other is a number then
-        returns a ConstantMultiplication operation object instead.
-        """
-        # Import here to avoid circular imports.
-        from b_asic.core_operations import Multiplication, ConstantMultiplication
-
-        if isinstance(other, Operation):
-            return Multiplication(self.output(0), other.output(0))
-        elif isinstance(other, Number):
-            return ConstantMultiplication(other, self.output(0))
+        if self.output_count == 1:
+            results[self.key(index, prefix)] = values[index]
         else:
-            raise TypeError("Other type is not an Operation or a Number.")
+            for i in range(self.output_count):
+                results[self.key(i, prefix)] = values[i]
+        return values[index]
 
-    def __truediv__(self, other):
-        """Overloads the division operator to make it return a new Division operation
-        object that is connected to the self and other objects. If other is a number then
-        returns a ConstantDivision operation object instead.
-        """
+    def current_outputs(self, registers: Optional[RegisterMap] = None, prefix: str = "") -> Sequence[Optional[Number]]:
+        return [self.current_output(i, registers, prefix) for i in range(self.output_count)]
+
+    def evaluate_outputs(self, input_values: Sequence[Number], results: Optional[MutableOutputMap] = None, registers: Optional[MutableRegisterMap] = None, prefix: str = "") -> Sequence[Number]:
+        return [self.evaluate_output(i, input_values, results, registers, prefix) for i in range(self.output_count)]
+
+    def split(self) -> Iterable[Operation]:
         # Import here to avoid circular imports.
-        from b_asic.core_operations import Division, ConstantDivision
+        from b_asic.special_operations import Input
+        try:
+            result = self.evaluate(*([Input()] * self.input_count))
+            if isinstance(result, collections.Sequence) and all(isinstance(e, Operation) for e in result):
+                return result
+            if isinstance(result, Operation):
+                return [result]
+        except TypeError:
+            pass
+        except ValueError:
+            pass
+        return [self]
 
-        if isinstance(other, Operation):
-            return Division(self.output(0), other.output(0))
-        elif isinstance(other, Number):
-            return ConstantDivision(other, self.output(0))
-        else:
-            raise TypeError("Other type is not an Operation or a Number.")
+    def inputs_required_for_output(self, output_index: int) -> Iterable[int]:
+        if output_index < 0 or output_index >= self.output_count:
+            raise IndexError(f"Output index out of range (expected 0-{self.output_count - 1}, got {output_index})")
+        return [i for i in range(self.input_count)]  # By default, assume each output depends on all inputs.
 
+    @property
+    def neighbors(self) -> Iterable[GraphComponent]:
+        return list(self.input_signals) + list(self.output_signals)
+
+    @property
+    def source(self) -> OutputPort:
+        if self.output_count != 1:
+            diff = "more" if self.output_count > 1 else "less"
+            raise TypeError(
+                f"{self.__class__.__name__} cannot be used as an input source because it has {diff} than 1 output")
+        return self.output(0)
+
+    def truncate_input(self, index: int, value: Number, bits: int) -> Number:
+        """Truncate the value to be used as input at the given index to a certain bit length."""
+        n = value
+        if not isinstance(n, int):
+            n = trunc(value)
+        return n & ((2 ** bits) - 1)
+
+    def truncate_inputs(self, input_values: Sequence[Number]) -> Sequence[Number]:
+        """Truncate the values to be used as inputs to the bit lengths specified by the respective signals connected to each input."""
+        args = []
+        for i, input_port in enumerate(self.inputs):
+            if input_port.signal_count >= 1:
+                bits = input_port.signals[0].bits
+                if bits is None:
+                    args.append(input_values[i])
+                else:
+                    if isinstance(input_values[i], complex):
+                        raise TypeError(
+                            "Complex value cannot be truncated to {bits} bits as requested by the signal connected to input #{i}")
+                    args.append(self.truncate_input(i, input_values[i], bits))
+            else:
+                args.append(input_values[i])
+        return args

b_asic/port.py

@@ -4,12 +4,15 @@ TODO: More info.
 """
 
 from abc import ABC, abstractmethod
-from typing import NewType, Optional, List
+from copy import copy
+from typing import Optional, List, Iterable, TYPE_CHECKING
 
-from b_asic.operation import Operation
 from b_asic.signal import Signal
+from b_asic.graph_component import Name
+
+if TYPE_CHECKING:
+    from b_asic.operation import Operation
 
-PortIndex = NewType("PortIndex", int)
 
 class Port(ABC):
     """Port Interface.
@@ -19,59 +22,33 @@ class Port(ABC):
 
     @property
     @abstractmethod
-    def operation(self) -> Operation:
+    def operation(self) -> "Operation":
         """Return the connected operation."""
         raise NotImplementedError
 
     @property
     @abstractmethod
-    def index(self) -> PortIndex:
-        """Return the unique PortIndex."""
+    def index(self) -> int:
+        """Return the index of the port."""
         raise NotImplementedError
 
     @property
-    @abstractmethod
-    def signals(self) -> List[Signal]:
-        """Return a list of all connected signals."""
-        raise NotImplementedError
-
-    @abstractmethod
-    def signal(self, i: int = 0) -> Signal:
-        """Return the connected signal at index i.
-
-        Keyword argumens:
-        i: integer index of the signal requsted.
-        """
-        raise NotImplementedError
-
-    @property
-    @abstractmethod
-    def connected_ports(self) -> List["Port"]:
-        """Return a list of all connected Ports."""
-        raise NotImplementedError
-
     @abstractmethod
     def signal_count(self) -> int:
         """Return the number of connected signals."""
         raise NotImplementedError
 
+    @property
     @abstractmethod
-    def connect(self, port: "Port") -> Signal:
-        """Create and return a signal that is connected to this port and the entered
-        port and connect this port to the signal and the entered port to the signal."""
+    def signals(self) -> Iterable[Signal]:
+        """Return all connected signals."""
         raise NotImplementedError
 
     @abstractmethod
     def add_signal(self, signal: Signal) -> None:
         """Connect this port to the entered signal. If the entered signal isn't connected to
-        this port then connect the entered signal to the port aswell."""
-        raise NotImplementedError
-
-    @abstractmethod
-    def disconnect(self, port: "Port") -> None:
-        """Disconnect the entered port from the port by removing it from the ports signal.
-        If the entered port is still connected to this ports signal then disconnect the entered
-        port from the signal aswell."""
+        this port then connect the entered signal to the port aswell.
+        """
         raise NotImplementedError
 
     @abstractmethod
@@ -97,22 +74,34 @@ class AbstractPort(Port):
     Handles functionality for port id and saves the connection to the parent operation.
     """
 
+    _operation: "Operation"
     _index: int
-    _operation: Operation
 
-    def __init__(self, index: int, operation: Operation):
-        self._index = index
+    def __init__(self, operation: "Operation", index: int):
         self._operation = operation
+        self._index = index
 
     @property
-    def operation(self) -> Operation:
+    def operation(self) -> "Operation":
         return self._operation
 
     @property
-    def index(self) -> PortIndex:
+    def index(self) -> int:
         return self._index
 
 
+class SignalSourceProvider(ABC):
+    """Signal source provider interface.
+    TODO: More info.
+    """
+
+    @property
+    @abstractmethod
+    def source(self) -> "OutputPort":
+        """Get the main source port provided by this object."""
+        raise NotImplementedError
+
+
 class InputPort(AbstractPort):
     """Input port.
     TODO: More info.
@@ -120,104 +109,82 @@ class InputPort(AbstractPort):
 
     _source_signal: Optional[Signal]
 
-    def __init__(self, port_id: PortIndex, operation: Operation):
-        super().__init__(port_id, operation)
+    def __init__(self, operation: "Operation", index: int):
+        super().__init__(operation, index)
         self._source_signal = None
 
     @property
-    def signals(self) -> List[Signal]:
-        return [] if self._source_signal is None else [self._source_signal]
-
-    def signal(self, i: int = 0) -> Signal:
-        assert 0 <= i < self.signal_count(), "Signal index out of bound."
-        assert self._source_signal is not None, "No Signal connect to InputPort."
-        return self._source_signal
-
-    @property
-    def connected_ports(self) -> List[Port]:
-        return [] if self._source_signal is None or self._source_signal.source is None \
-            else [self._source_signal.source]
-
     def signal_count(self) -> int:
         return 0 if self._source_signal is None else 1
 
-    def connect(self, port: "OutputPort") -> Signal:
-        assert self._source_signal is None, "Connecting new port to already connected input port."
-        return Signal(port, self)        # self._source_signal is set by the signal constructor
+    @property
+    def signals(self) -> Iterable[Signal]:
+        return [] if self._source_signal is None else [self._source_signal]
 
     def add_signal(self, signal: Signal) -> None:
-        assert self._source_signal is None, "Connecting new port to already connected input port."
-        self._source_signal: Signal = signal
-        if self is not signal.destination:
-            # Connect this inputport as destination for this signal if it isn't already.
-            signal.set_destination(self)
-
-    def disconnect(self, port: "OutputPort") -> None:
-        assert self._source_signal.source is port, "The entered port is not connected to this port."
-        self._source_signal.remove_source()
+        assert self._source_signal is None, "Input port may have only one signal added."
+        assert signal is not self._source_signal, "Attempted to add already connected signal."
+        self._source_signal = signal
+        signal.set_destination(self)
 
     def remove_signal(self, signal: Signal) -> None:
-        old_signal: Signal = self._source_signal
+        assert signal is self._source_signal, "Attempted to remove already removed signal."
         self._source_signal = None
-        if self is old_signal.destination:
-            # Disconnect the dest of the signal if this inputport currently is the dest
-            old_signal.remove_destination()
+        signal.remove_destination()
 
     def clear(self) -> None:
-        self.remove_signal(self._source_signal)
+        if self._source_signal is not None:
+            self.remove_signal(self._source_signal)
 
-class OutputPort(AbstractPort):
+    @property
+    def connected_source(self) -> Optional["OutputPort"]:
+        """Get the output port that is currently connected to this input port,
+        or None if it is unconnected.
+        """
+        return None if self._source_signal is None else self._source_signal.source
+
+    def connect(self, src: SignalSourceProvider, name: Name = "") -> Signal:
+        """Connect the provided signal source to this input port by creating a new signal.
+        Returns the new signal.
+        """
+        assert self._source_signal is None, "Attempted to connect already connected input port."
+        # self._source_signal is set by the signal constructor.
+        return Signal(source=src.source, destination=self, name=name)
+
+
+class OutputPort(AbstractPort, SignalSourceProvider):
     """Output port.
     TODO: More info.
     """
 
     _destination_signals: List[Signal]
 
-    def __init__(self, port_id: PortIndex, operation: Operation):
-        super().__init__(port_id, operation)
+    def __init__(self, operation: "Operation", index: int):
+        super().__init__(operation, index)
         self._destination_signals = []
 
     @property
-    def signals(self) -> List[Signal]:
-        return self._destination_signals.copy()
-
-    def signal(self, i: int = 0) -> Signal:
-        assert 0 <= i < self.signal_count(), "Signal index out of bounds."
-        return self._destination_signals[i]
-
-    @property
-    def connected_ports(self) -> List[Port]:
-        return [signal.destination for signal in self._destination_signals \
-            if signal.destination is not None]
-
     def signal_count(self) -> int:
         return len(self._destination_signals)
 
-    def connect(self, port: InputPort) -> Signal:
-        return Signal(self, port)      # Signal is added to self._destination_signals in signal constructor
+    @property
+    def signals(self) -> Iterable[Signal]:
+        return self._destination_signals
 
     def add_signal(self, signal: Signal) -> None:
-        assert signal not in self.signals, \
-                "Attempting to connect to Signal already connected."
+        assert signal not in self._destination_signals, "Attempted to add already connected signal."
         self._destination_signals.append(signal)
-        if self is not signal.source:
-            # Connect this outputport to the signal if it isn't already
-            signal.set_source(self)
-
-    def disconnect(self, port: InputPort) -> None:
-        assert port in self.connected_ports, "Attempting to disconnect port that isn't connected."
-        for sig in self._destination_signals:
-            if sig.destination is port:
-                sig.remove_destination()
-                break
+        signal.set_source(self)
 
     def remove_signal(self, signal: Signal) -> None:
-        i: int = self._destination_signals.index(signal)
-        old_signal: Signal = self._destination_signals[i]
-        del self._destination_signals[i]
-        if self is old_signal.source:
-            old_signal.remove_source()
+        assert signal in self._destination_signals, "Attempted to remove already removed signal."
+        self._destination_signals.remove(signal)
+        signal.remove_source()
 
     def clear(self) -> None:
-        for signal in self._destination_signals:
+        for signal in copy(self._destination_signals):
             self.remove_signal(signal)
+
+    @property
+    def source(self) -> "OutputPort":
+        return self

b_asic/precedence_chart.py

-"""@package docstring
-B-ASIC Precedence Chart Module.
-TODO: More info.
-"""
-
-from b_asic.signal_flow_graph import SFG
-
-
-class PrecedenceChart:
-    """Precedence chart constructed from a signal flow graph.
-    TODO: More info.
-    """
-
-    sfg: SFG
-    # TODO: More members.
-
-    def __init__(self, sfg: SFG):
-        self.sfg = sfg
-        # TODO: Implement.
-
-    # TODO: More stuff.

b_asic/schema.py

-"""@package docstring
-B-ASIC Schema Module.
-TODO: More info.
-"""
-
-from b_asic.precedence_chart import PrecedenceChart
-
-
-class Schema:
-    """Schema constructed from a precedence chart.
-    TODO: More info.
-    """
-
-    pc: PrecedenceChart
-    # TODO: More members.
-
-    def __init__(self, pc: PrecedenceChart):
-        self.pc = pc
-        # TODO: Implement.
-
-    # TODO: More stuff.

b_asic/signal.py

 """@package docstring
 B-ASIC Signal Module.
 """
-from typing import Optional, TYPE_CHECKING
+from typing import Optional, Iterable, TYPE_CHECKING
 
-from b_asic.graph_component import AbstractGraphComponent, TypeName, Name
+from b_asic.graph_component import GraphComponent, AbstractGraphComponent, TypeName, Name
 
 if TYPE_CHECKING:
     from b_asic.port import InputPort, OutputPort
@@ -12,30 +12,34 @@ if TYPE_CHECKING:
 class Signal(AbstractGraphComponent):
     """A connection between two ports."""
 
-    _source: "OutputPort"
-    _destination: "InputPort"
-
-    def __init__(self, source: Optional["OutputPort"] = None, \
-                destination: Optional["InputPort"] = None, name: Name = ""):
+    _source: Optional["OutputPort"]
+    _destination: Optional["InputPort"]
 
+    def __init__(self, source: Optional["OutputPort"] = None, destination: Optional["InputPort"] = None, bits: Optional[int] = None, name: Name = ""):
         super().__init__(name)
-
-        self._source = source
-        self._destination = destination
-
+        self._source = None
+        self._destination = None
         if source is not None:
             self.set_source(source)
-
         if destination is not None:
             self.set_destination(destination)
+        self.set_param("bits", bits)
+
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "s"
 
     @property
-    def source(self) -> "OutputPort":
+    def neighbors(self) -> Iterable[GraphComponent]:
+        return [p.operation for p in [self.source, self.destination] if p is not None]
+
+    @property
+    def source(self) -> Optional["OutputPort"]:
         """Return the source OutputPort of the signal."""
         return self._source
 
     @property
-    def destination(self) -> "InputPort":
+    def destination(self) -> Optional["InputPort"]:
         """Return the destination "InputPort" of the signal."""
         return self._destination
 
@@ -47,11 +51,11 @@ class Signal(AbstractGraphComponent):
         Keyword arguments:
         - src: OutputPort to connect as source to the signal.
         """
-        self.remove_source()
-        self._source = src
-        if self not in src.signals:
-            # If the new source isn't connected to this signal then connect it.
-            src.add_signal(self)
+        if src is not self._source:
+            self.remove_source()
+            self._source = src
+            if self not in src.signals:
+                src.add_signal(self)
 
     def set_destination(self, dest: "InputPort") -> None:
         """Disconnect the previous destination InputPort of the signal and
@@ -61,36 +65,44 @@ class Signal(AbstractGraphComponent):
         Keywords argments:
         - dest: InputPort to connect as destination to the signal.
         """
-        self.remove_destination()
-        self._destination = dest
-        if self not in dest.signals:
-            # If the new destination isn't connected to tis signal then connect it.
-            dest.add_signal(self)
-
-    @property
-    def type_name(self) -> TypeName:
-        return "s"
+        if dest is not self._destination:
+            self.remove_destination()
+            self._destination = dest
+            if self not in dest.signals:
+                dest.add_signal(self)
 
     def remove_source(self) -> None:
         """Disconnect the source OutputPort of the signal. If the source port
         still is connected to this signal then also disconnect the source port."""
-        if self._source is not None:
-            old_source: "OutputPort" = self._source
+        src = self._source
+        if src is not None:
             self._source = None
-            if self in old_source.signals:
-                # If the old destination port still is connected to this signal, then disconnect it.
-                old_source.remove_signal(self)
+            if self in src.signals:
+                src.remove_signal(self)
 
     def remove_destination(self) -> None:
         """Disconnect the destination InputPort of the signal."""
-        if self._destination is not None:
-            old_destination: "InputPort" = self._destination
+        dest = self._destination
+        if dest is not None:
             self._destination = None
-            if self in old_destination.signals:
-                # If the old destination port still is connected to this signal, then disconnect it.
-                old_destination.remove_signal(self)
+            if self in dest.signals:
+                dest.remove_signal(self)
 
-    def is_connected(self) -> bool:
-        """Returns true if the signal is connected to both a source and a destination,
+    def dangling(self) -> bool:
+        """Returns true if the signal is missing either a source or a destination,
         else false."""
-        return self._source is not None and self._destination is not None
+        return self._source is None or self._destination is None
+
+    @property
+    def bits(self) -> Optional[int]:
+        """Get the number of bits that this operations using this signal as an input should truncate received values to.
+        None = unlimited."""
+        return self.param("bits")
+
+    @bits.setter
+    def bits(self, bits: Optional[int]) -> None:
+        """Set the number of bits that operations using this signal as an input should truncate received values to.
+        None = unlimited."""
+        assert bits is None or (isinstance(bits, int)
+                                and bits >= 0), "Bits must be non-negative."
+        self.set_param("bits", bits)

b_asic/signal_flow_graph.py

@@ -3,14 +3,35 @@ B-ASIC Signal Flow Graph Module.
 TODO: More info.
 """
 
-from typing import List, Dict, Optional, DefaultDict
-from collections import defaultdict
+from typing import List, Iterable, Sequence, Dict, Optional, DefaultDict, MutableSet
+from numbers import Number
+from collections import defaultdict, deque
 
-from b_asic.operation import Operation
-from b_asic.operation import AbstractOperation
+from b_asic.port import SignalSourceProvider, OutputPort, InputPort
+from b_asic.operation import Operation, AbstractOperation, MutableOutputMap, MutableRegisterMap
 from b_asic.signal import Signal
-from b_asic.graph_id import GraphIDGenerator, GraphID
-from b_asic.graph_component import GraphComponent, Name, TypeName
+from b_asic.graph_component import GraphID, GraphIDNumber, GraphComponent, Name, TypeName
+from b_asic.special_operations import Input, Output, Register
+from b_asic.core_operations import Constant
+
+
+class GraphIDGenerator:
+    """A class that generates Graph IDs for objects."""
+
+    _next_id_number: DefaultDict[TypeName, GraphIDNumber]
+
+    def __init__(self, id_number_offset: GraphIDNumber = 0):
+        self._next_id_number = defaultdict(lambda: id_number_offset)
+
+    def next_id(self, type_name: TypeName) -> GraphID:
+        """Get the next graph id for a certain graph id type."""
+        self._next_id_number[type_name] += 1
+        return type_name + str(self._next_id_number[type_name])
+
+    @property
+    def id_number_offset(self) -> GraphIDNumber:
+        """Get the graph id number offset of this generator."""
+        return self._next_id_number.default_factory()  # pylint: disable=not-callable
 
 
 class SFG(AbstractOperation):
@@ -18,74 +39,589 @@ class SFG(AbstractOperation):
     TODO: More info.
     """
 
-    _graph_components_by_id: Dict[GraphID, GraphComponent]
-    _graph_components_by_name: DefaultDict[Name, List[GraphComponent]]
+    _components_by_id: Dict[GraphID, GraphComponent]
+    _components_by_name: DefaultDict[Name, List[GraphComponent]]
+    _components_ordered: List[GraphComponent]
+    _operations_ordered: List[Operation]
     _graph_id_generator: GraphIDGenerator
+    _input_operations: List[Input]
+    _output_operations: List[Output]
+    _original_components_to_new: MutableSet[GraphComponent]
+    _original_input_signals_to_indices: Dict[Signal, int]
+    _original_output_signals_to_indices: Dict[Signal, int]
+    _precedence_list: Optional[List[List[OutputPort]]]
+
+    def __init__(self, input_signals: Optional[Sequence[Signal]] = None, output_signals: Optional[Sequence[Signal]] = None,
+                 inputs: Optional[Sequence[Input]] = None, outputs: Optional[Sequence[Output]] = None,
+                 id_number_offset: GraphIDNumber = 0, name: Name = "",
+                 input_sources: Optional[Sequence[Optional[SignalSourceProvider]]] = None):
+
+        input_signal_count = 0 if input_signals is None else len(input_signals)
+        input_operation_count = 0 if inputs is None else len(inputs)
+        output_signal_count = 0 if output_signals is None else len(
+            output_signals)
+        output_operation_count = 0 if outputs is None else len(outputs)
+        super().__init__(input_count=input_signal_count + input_operation_count,
+                         output_count=output_signal_count + output_operation_count,
+                         name=name, input_sources=input_sources)
+
+        self._components_by_id = dict()
+        self._components_by_name = defaultdict(list)
+        self._components_ordered = []
+        self._operations_ordered = []
+        self._graph_id_generator = GraphIDGenerator(id_number_offset)
+        self._input_operations = []
+        self._output_operations = []
+        self._original_components_to_new = {}
+        self._original_input_signals_to_indices = {}
+        self._original_output_signals_to_indices = {}
+        self._precedence_list = None
+
+        # Setup input signals.
+        if input_signals is not None:
+            for input_index, signal in enumerate(input_signals):
+                assert signal not in self._original_components_to_new, "Duplicate input signals supplied to SFG construcctor."
+                new_input_op = self._add_component_unconnected_copy(Input())
+                new_signal = self._add_component_unconnected_copy(signal)
+                new_signal.set_source(new_input_op.output(0))
+                self._input_operations.append(new_input_op)
+                self._original_input_signals_to_indices[signal] = input_index
+
+        # Setup input operations, starting from indices ater input signals.
+        if inputs is not None:
+            for input_index, input_op in enumerate(inputs, input_signal_count):
+                assert input_op not in self._original_components_to_new, "Duplicate input operations supplied to SFG constructor."
+                new_input_op = self._add_component_unconnected_copy(input_op)
+                for signal in input_op.output(0).signals:
+                    assert signal not in self._original_components_to_new, "Duplicate input signals connected to input ports supplied to SFG construcctor."
+                    new_signal = self._add_component_unconnected_copy(signal)
+                    new_signal.set_source(new_input_op.output(0))
+                    self._original_input_signals_to_indices[signal] = input_index
 
-    def __init__(self, input_signals: List[Signal] = None, output_signals: List[Signal] = None, \
-                ops: List[Operation] = None, **kwds):
-        super().__init__(**kwds)
-        if input_signals is None:
-            input_signals = []
-        if output_signals is None:
-            output_signals = []
-        if ops is None:
-            ops = []
+                self._input_operations.append(new_input_op)
 
-        self._graph_components_by_id = dict() # Maps Graph ID to objects
-        self._graph_components_by_name = defaultdict(list) # Maps Name to objects
-        self._graph_id_generator = GraphIDGenerator()
+        # Setup output signals.
+        if output_signals is not None:
+            for output_index, signal in enumerate(output_signals):
+                new_output_op = self._add_component_unconnected_copy(Output())
+                if signal in self._original_components_to_new:
+                    # Signal was already added when setting up inputs.
+                    new_signal = self._original_components_to_new[signal]
+                    new_signal.set_destination(new_output_op.input(0))
+                else:
+                    # New signal has to be created.
+                    new_signal = self._add_component_unconnected_copy(signal)
+                    new_signal.set_destination(new_output_op.input(0))
 
-        for operation in ops:
-            self._add_graph_component(operation)
+                self._output_operations.append(new_output_op)
+                self._original_output_signals_to_indices[signal] = output_index
 
-        for input_signal in input_signals:
-            self._add_graph_component(input_signal)
+        # Setup output operations, starting from indices after output signals.
+        if outputs is not None:
+            for output_index, output_op in enumerate(outputs, output_signal_count):
+                assert output_op not in self._original_components_to_new, "Duplicate output operations supplied to SFG constructor."
+                new_output_op = self._add_component_unconnected_copy(output_op)
+                for signal in output_op.input(0).signals:
+                    new_signal = None
+                    if signal in self._original_components_to_new:
+                        # Signal was already added when setting up inputs.
+                        new_signal = self._original_components_to_new[signal]
+                    else:
+                        # New signal has to be created.
+                        new_signal = self._add_component_unconnected_copy(
+                            signal)
 
-        # TODO: Construct SFG based on what inputs that were given
-        # TODO: Traverse the graph between the inputs/outputs and add to self._operations.
-        # TODO: Connect ports with signals with appropriate IDs.
+                    new_signal.set_destination(new_output_op.input(0))
+                    self._original_output_signals_to_indices[signal] = output_index
 
-    def evaluate(self, *inputs) -> list:
-        return [] # TODO: Implement
+                self._output_operations.append(new_output_op)
+
+        output_operations_set = set(self._output_operations)
+
+        # Search the graph inwards from each input signal.
+        for signal, input_index in self._original_input_signals_to_indices.items():
+            # Check if already added destination.
+            new_signal = self._original_components_to_new[signal]
+            if new_signal.destination is None:
+                if signal.destination is None:
+                    raise ValueError(
+                        f"Input signal #{input_index} is missing destination in SFG")
+                if signal.destination.operation not in self._original_components_to_new:
+                    self._add_operation_connected_tree_copy(
+                        signal.destination.operation)
+            elif new_signal.destination.operation in output_operations_set:
+                # Add directly connected input to output to ordered list.
+                self._components_ordered.extend(
+                    [new_signal.source.operation, new_signal, new_signal.destination.operation])
+                self._operations_ordered.extend(
+                    [new_signal.source.operation, new_signal.destination.operation])
+
+        # Search the graph inwards from each output signal.
+        for signal, output_index in self._original_output_signals_to_indices.items():
+            # Check if already added source.
+            new_signal = self._original_components_to_new[signal]
+            if new_signal.source is None:
+                if signal.source is None:
+                    raise ValueError(
+                        f"Output signal #{output_index} is missing source in SFG")
+                if signal.source.operation not in self._original_components_to_new:
+                    self._add_operation_connected_tree_copy(
+                        signal.source.operation)
+
+    def __str__(self) -> str:
+        """Get a string representation of this SFG."""
+        output_string = ""
+        for component in self._components_ordered:
+            if isinstance(component, Operation):
+                for key, value in self._components_by_id.items():
+                    if value is component:
+                        output_string += "id: " + key + ", name: "
+
+                if component.name != None:
+                    output_string += component.name + ", "
+                else:
+                    output_string += "-, "
+
+                if isinstance(component, Constant):
+                    output_string += "value: " + \
+                        str(component.value) + ", input: ["
+                else:
+                    output_string += "input: ["
+
+                counter_input = 0
+                for input in component.inputs:
+                    counter_input += 1
+                    for signal in input.signals:
+                        for key, value in self._components_by_id.items():
+                            if value is signal:
+                                output_string += key + ", "
+
+                if counter_input > 0:
+                    output_string = output_string[:-2]
+                output_string += "], output: ["
+                counter_output = 0
+                for output in component.outputs:
+                    counter_output += 1
+                    for signal in output.signals:
+                        for key, value in self._components_by_id.items():
+                            if value is signal:
+                                output_string += key + ", "
+                if counter_output > 0:
+                    output_string = output_string[:-2]
+                output_string += "]\n"
+
+        return output_string
+
+    def __call__(self, *src: Optional[SignalSourceProvider], name: Name = "") -> "SFG":
+        """Get a new independent SFG instance that is identical to this SFG except without any of its external connections."""
+        return SFG(inputs=self._input_operations, outputs=self._output_operations,
+                   id_number_offset=self.id_number_offset, name=name, input_sources=src if src else None)
+
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "sfg"
 
-    def _add_graph_component(self, graph_component: GraphComponent) -> GraphID:
-        """Add the entered graph component to the SFG's dictionary of graph objects and
-         return a generated GraphID for it.
+    def evaluate(self, *args):
+        result = self.evaluate_outputs(args, {}, {}, "")
+        n = len(result)
+        return None if n == 0 else result[0] if n == 1 else result
+
+    def evaluate_output(self, index: int, input_values: Sequence[Number], results: Optional[MutableOutputMap] = None, registers: Optional[MutableRegisterMap] = None, prefix: str = "") -> Number:
+        if index < 0 or index >= self.output_count:
+            raise IndexError(
+                f"Output index out of range (expected 0-{self.output_count - 1}, got {index})")
+        if len(input_values) != self.input_count:
+            raise ValueError(
+                f"Wrong number of inputs supplied to SFG for evaluation (expected {self.input_count}, got {len(input_values)})")
+        if results is None:
+            results = {}
+        if registers is None:
+            registers = {}
+
+        # Set the values of our input operations to the given input values.
+        for op, arg in zip(self._input_operations, self.truncate_inputs(input_values)):
+            op.value = arg
+
+        value = self._evaluate_source(self._output_operations[index].input(
+            0).signals[0].source, results, registers, prefix)
+        results[self.key(index, prefix)] = value
+        return value
+
+    def connect_external_signals_to_components(self) -> bool:
+        """ Connects any external signals to this SFG's internal operations. This SFG becomes unconnected to the SFG 
+        it is a component off, causing it to become invalid afterwards. Returns True if succesful, False otherwise. """
+        if len(self.inputs) != len(self.input_operations):
+            raise IndexError(f"Number of inputs does not match the number of input_operations in SFG.")
+        if len(self.outputs) != len(self.output_operations):
+            raise IndexError(f"Number of outputs does not match the number of output_operations SFG.")
+        if len(self.input_signals) == 0:
+            return False
+        if len(self.output_signals) == 0:
+            return False
+
+        # For each input_signal, connect it to the corresponding operation
+        for port, input_operation in zip(self.inputs, self.input_operations):
+            dest = input_operation.output(0).signals[0].destination
+            dest.clear()
+            port.signals[0].set_destination(dest)
+        # For each output_signal, connect it to the corresponding operation    
+        for port, output_operation in zip(self.outputs, self.output_operations):
+            src = output_operation.input(0).signals[0].source
+            src.clear()
+            port.signals[0].set_source(src)
+        return True
+
+    @property
+    def input_operations(self) -> Sequence[Operation]:
+        """Get the internal input operations in the same order as their respective input ports."""
+        return self._input_operations
+
+    @property
+    def output_operations(self) -> Sequence[Operation]:
+        """Get the internal output operations in the same order as their respective output ports."""
+        return self._output_operations
+
+    def split(self) -> Iterable[Operation]:
+        return self.operations
+
+    def inputs_required_for_output(self, output_index: int) -> Iterable[int]:
+        if output_index < 0 or output_index >= self.output_count:
+            raise IndexError(
+                f"Output index out of range (expected 0-{self.output_count - 1}, got {output_index})")
+
+        input_indexes_required = []
+        sfg_input_operations_to_indexes = {
+            input_op: index for index, input_op in enumerate(self._input_operations)}
+        output_op = self._output_operations[output_index]
+        queue = deque([output_op])
+        visited = set([output_op])
+        while queue:
+            op = queue.popleft()
+            if isinstance(op, Input):
+                if op in sfg_input_operations_to_indexes:
+                    input_indexes_required.append(
+                        sfg_input_operations_to_indexes[op])
+                    del sfg_input_operations_to_indexes[op]
+
+            for input_port in op.inputs:
+                for signal in input_port.signals:
+                    if signal.source is not None:
+                        new_op = signal.source.operation
+                        if new_op not in visited:
+                            queue.append(new_op)
+                            visited.add(new_op)
+
+        return input_indexes_required
+
+    def copy_component(self, *args, **kwargs) -> GraphComponent:
+        return super().copy_component(*args, **kwargs, inputs=self._input_operations, outputs=self._output_operations,
+                                      id_number_offset=self.id_number_offset, name=self.name)
+
+    @property
+    def id_number_offset(self) -> GraphIDNumber:
+        """Get the graph id number offset of the graph id generator for this SFG."""
+        return self._graph_id_generator.id_number_offset
+
+    @property
+    def components(self) -> Iterable[GraphComponent]:
+        """Get all components of this graph in depth-first order."""
+        return self._components_ordered
+
+    @property
+    def operations(self) -> Iterable[Operation]:
+        """Get all operations of this graph in depth-first order."""
+        return self._operations_ordered
+
+    def get_components_with_type_name(self, type_name: TypeName) -> List[GraphComponent]:
+        """Get a list with all components in this graph with the specified type_name.
 
         Keyword arguments:
-        graph_component: Graph component to add to the graph.
+        type_name: The type_name of the desired components.
         """
-        # Add to name dict
-        self._graph_components_by_name[graph_component.name].append(graph_component)
+        i = self.id_number_offset + 1
+        components = []
+        found_comp = self.find_by_id(type_name + str(i))
+        while found_comp is not None:
+            components.append(found_comp)
+            i += 1
+            found_comp = self.find_by_id(type_name + str(i))
 
-        # Add to ID dict
-        graph_id: GraphID = self._graph_id_generator.get_next_id(graph_component.type_name)
-        self._graph_components_by_id[graph_id] = graph_component
-        return graph_id
+        return components
 
     def find_by_id(self, graph_id: GraphID) -> Optional[GraphComponent]:
-        """Find a graph object based on the entered Graph ID and return it. If no graph
-        object with the entered ID was found then return None.
+        """Find the graph component with the specified ID.
+        Returns None if the component was not found.
 
         Keyword arguments:
-        graph_id: Graph ID of the wanted object.
+        graph_id: Graph ID of the desired component.
         """
-        if graph_id in self._graph_components_by_id:
-            return self._graph_components_by_id[graph_id]
-
-        return None
+        return self._components_by_id.get(graph_id, None)
 
-    def find_by_name(self, name: Name) -> List[GraphComponent]:
-        """Find all graph objects that have the entered name and return them
-        in a list. If no graph object with the entered name was found then return an
-        empty list.
+    def find_by_name(self, name: Name) -> Sequence[GraphComponent]:
+        """Find all graph components with the specified name.
+        Returns an empty sequence if no components were found.
 
         Keyword arguments:
-        name: Name of the wanted object.
+        name: Name of the desired component(s)
         """
-        return self._graph_components_by_name[name]
+        return self._components_by_name.get(name, [])
 
-    @property
-    def type_name(self) -> TypeName:
-        return "sfg"
+    def _add_component_unconnected_copy(self, original_component: GraphComponent) -> GraphComponent:
+        assert original_component not in self._original_components_to_new, "Tried to add duplicate SFG component"
+        new_component = original_component.copy_component()
+        self._original_components_to_new[original_component] = new_component
+        new_id = self._graph_id_generator.next_id(new_component.type_name())
+        new_component.graph_id = new_id
+        self._components_by_id[new_id] = new_component
+        self._components_by_name[new_component.name].append(new_component)
+        return new_component
+
+    def _add_operation_connected_tree_copy(self, start_op: Operation) -> None:
+        op_stack = deque([start_op])
+        while op_stack:
+            original_op = op_stack.pop()
+            # Add or get the new copy of the operation.
+            new_op = None
+            if original_op not in self._original_components_to_new:
+                new_op = self._add_component_unconnected_copy(original_op)
+                self._components_ordered.append(new_op)
+                self._operations_ordered.append(new_op)
+            else:
+                new_op = self._original_components_to_new[original_op]
+
+            # Connect input ports to new signals.
+            for original_input_port in original_op.inputs:
+                if original_input_port.signal_count < 1:
+                    raise ValueError("Unconnected input port in SFG")
+
+                for original_signal in original_input_port.signals:
+                    # Check if the signal is one of the SFG's input signals.
+                    if original_signal in self._original_input_signals_to_indices:
+                        # New signal already created during first step of constructor.
+                        new_signal = self._original_components_to_new[original_signal]
+                        new_signal.set_destination(
+                            new_op.input(original_input_port.index))
+                        self._components_ordered.extend(
+                            [new_signal, new_signal.source.operation])
+                        self._operations_ordered.append(
+                            new_signal.source.operation)
+
+                    # Check if the signal has not been added before.
+                    elif original_signal not in self._original_components_to_new:
+                        if original_signal.source is None:
+                            raise ValueError(
+                                "Dangling signal without source in SFG")
+
+                        new_signal = self._add_component_unconnected_copy(
+                            original_signal)
+                        new_signal.set_destination(
+                            new_op.input(original_input_port.index))
+                        self._components_ordered.append(new_signal)
+
+                        original_connected_op = original_signal.source.operation
+                        # Check if connected Operation has been added before.
+                        if original_connected_op in self._original_components_to_new:
+                            # Set source to the already added operations port.
+                            new_signal.set_source(self._original_components_to_new[original_connected_op].output(
+                                original_signal.source.index))
+                        else:
+                            # Create new operation, set signal source to it.
+                            new_connected_op = self._add_component_unconnected_copy(
+                                original_connected_op)
+                            new_signal.set_source(new_connected_op.output(
+                                original_signal.source.index))
+                            self._components_ordered.append(new_connected_op)
+                            self._operations_ordered.append(new_connected_op)
+
+                            # Add connected operation to queue of operations to visit.
+                            op_stack.append(original_connected_op)
+
+            # Connect output ports.
+            for original_output_port in original_op.outputs:
+                for original_signal in original_output_port.signals:
+                    # Check if the signal is one of the SFG's output signals.
+                    if original_signal in self._original_output_signals_to_indices:
+                        # New signal already created during first step of constructor.
+                        new_signal = self._original_components_to_new[original_signal]
+                        new_signal.set_source(
+                            new_op.output(original_output_port.index))
+                        self._components_ordered.extend(
+                            [new_signal, new_signal.destination.operation])
+                        self._operations_ordered.append(
+                            new_signal.destination.operation)
+
+                    # Check if signal has not been added before.
+                    elif original_signal not in self._original_components_to_new:
+                        if original_signal.source is None:
+                            raise ValueError(
+                                "Dangling signal without source in SFG")
+
+                        new_signal = self._add_component_unconnected_copy(
+                            original_signal)
+                        new_signal.set_source(
+                            new_op.output(original_output_port.index))
+                        self._components_ordered.append(new_signal)
+
+                        original_connected_op = original_signal.destination.operation
+                        # Check if connected operation has been added.
+                        if original_connected_op in self._original_components_to_new:
+                            # Set destination to the already connected operations port.
+                            new_signal.set_destination(self._original_components_to_new[original_connected_op].input(
+                                original_signal.destination.index))
+                        else:
+                            # Create new operation, set destination to it.
+                            new_connected_op = self._add_component_unconnected_copy(
+                                original_connected_op)
+                            new_signal.set_destination(new_connected_op.input(
+                                original_signal.destination.index))
+                            self._components_ordered.append(new_connected_op)
+                            self._operations_ordered.append(new_connected_op)
+
+                            # Add connected operation to the queue of operations to visit.
+                            op_stack.append(original_connected_op)
+
+    def replace_component(self, component: Operation, _id: GraphID):
+        """Find and replace all components matching either on GraphID, Type or both.
+        Then return a new deepcopy of the sfg with the replaced component.
+
+        Arguments:
+        component: The new component(s), e.g Multiplication
+        _id: The GraphID to match the component to replace.
+        """
+
+        _sfg_copy = self()
+        _component = _sfg_copy.find_by_id(_id)
+
+        assert _component is not None and isinstance(_component, Operation), \
+            "No operation matching the criteria found"
+        assert _component.output_count == component.output_count, \
+            "The output count may not differ between the operations"
+        assert _component.input_count == component.input_count, \
+            "The input count may not differ between the operations"
+
+        for index_in, _inp in enumerate(_component.inputs):
+            for _signal in _inp.signals:
+                _signal.remove_destination()
+                _signal.set_destination(component.input(index_in))
+
+        for index_out, _out in enumerate(_component.outputs):
+            for _signal in _out.signals:
+                _signal.remove_source()
+                _signal.set_source(component.output(index_out))
+
+        # The old SFG will be deleted by Python GC
+        return _sfg_copy()
+
+    def insert_operation(self, component: Operation, output_comp_id: GraphID):
+        """Insert an operation in the SFG after a given source operation.
+        The source operation output count must match the input count of the operation as well as the output
+        Then return a new deepcopy of the sfg with the inserted component.
+
+        Arguments:
+        component: The new component, e.g Multiplication.
+        output_comp_id: The source operation GraphID to connect from.
+        """
+
+        # Preserve the original SFG by creating a copy.
+        sfg_copy = self()
+        output_comp = sfg_copy.find_by_id(output_comp_id)
+        if output_comp is None:
+            return None
+
+        assert not isinstance(output_comp, Output), \
+            "Source operation can not be an output operation."
+        assert len(output_comp.output_signals) == component.input_count, \
+            "Source operation output count does not match input count for component."
+        assert len(output_comp.output_signals) == component.output_count, \
+            "Destination operation input count does not match output for component."
+
+        for index, signal_in in enumerate(output_comp.output_signals):
+            destination = signal_in.destination
+            signal_in.set_destination(component.input(index))
+            destination.connect(component.output(index))
+
+        # Recreate the newly coupled SFG so that all attributes are correct.
+        return sfg_copy()
+
+    def explode(self) -> Tuple[Sequence[Signal, Sequence[Signal]], Sequence[Tuple[Signal, Sequence[Signal]]]:
+    """Destroy the sfg by making it unusable in the future and 
+    return all of the intermidetry operations, the input operations and the output operations.
+    """
+    return
+
+    def _evaluate_source(self, src: OutputPort, results: MutableOutputMap, registers: MutableRegisterMap, prefix: str) -> Number:
+        src_prefix = prefix
+        if src_prefix:
+            src_prefix += "."
+        src_prefix += src.operation.graph_id
+
+        key = src.operation.key(src.index, src_prefix)
+        if key in results:
+            value = results[key]
+            if value is None:
+                raise RuntimeError(
+                    f"Direct feedback loop detected when evaluating operation.")
+            return value
+
+        results[key] = src.operation.current_output(
+            src.index, registers, src_prefix)
+        input_values = [self._evaluate_source(
+            input_port.signals[0].source, results, registers, prefix) for input_port in src.operation.inputs]
+        value = src.operation.evaluate_output(
+            src.index, input_values, results, registers, src_prefix)
+        results[key] = value
+        return value
+
+    def get_precedence_list(self) -> List[List[OutputPort]]:
+        """Returns a Precedence list of the SFG where each element in n:th the list consists
+        of elements that are executed in the n:th step. If the precedence list already has been
+        calculated for the current SFG then returns the cached version."""
+        if self._precedence_list is not None:
+            return self._precedence_list
+
+        # Find all operations with only outputs and no inputs.
+        no_input_ops = list(filter(lambda op: op.input_count == 0, self.operations))
+        reg_ops = self.get_components_with_type_name(Register.type_name())
+
+        # Find all first iter output ports for precedence
+        first_iter_ports = [op.output(i) for op in (no_input_ops + reg_ops) for i in range(op.output_count)]
+
+        self._precedence_list = self._traverse_for_precedence_list(first_iter_ports)
+
+        return self._precedence_list
+
+    def _traverse_for_precedence_list(self, first_iter_ports):
+        # Find dependencies of output ports and input ports.
+        outports_per_inport = defaultdict(list)
+        remaining_inports_per_outport = dict()
+        for op in self.operations:
+            op_inputs = op.inputs
+            for out_i, outport in enumerate(op.outputs):
+                dependendent_indexes = op.inputs_required_for_output(out_i)
+                remaining_inports_per_outport[outport] = len(dependendent_indexes)
+                for in_i in dependendent_indexes:
+                    outports_per_inport[op_inputs[in_i]].append(outport)
+
+        # Traverse output ports for precedence
+        curr_iter_ports = first_iter_ports
+        precedence_list = []
+
+        while curr_iter_ports:
+            # Add the found ports to the current iter
+            precedence_list.append(curr_iter_ports)
+
+            next_iter_ports = []
+
+            for outport in curr_iter_ports:
+                for signal in outport.signals:
+                    new_inport = signal.destination
+                    # Don't traverse over Registers
+                    if new_inport is not None and not isinstance(new_inport.operation, Register):
+                        for new_outport in outports_per_inport[new_inport]:
+                            remaining_inports_per_outport[new_outport] -= 1
+                            if remaining_inports_per_outport[new_outport] == 0:
+                                next_iter_ports.append(new_outport)
+
+            curr_iter_ports = next_iter_ports
+
+        return precedence_list

b_asic/simulation.py

@@ -3,33 +3,116 @@ B-ASIC Simulation Module.
 TODO: More info.
 """
 
+from collections import defaultdict
 from numbers import Number
-from typing import List
+from typing import List, Dict, DefaultDict, Callable, Sequence, Mapping, Union, Optional
 
+from b_asic.operation import OutputKey, OutputMap
+from b_asic.signal_flow_graph import SFG
 
-class OperationState:
-    """Simulation state of an operation.
+
+InputProvider = Union[Number, Sequence[Number], Callable[[int], Number]]
+
+
+class Simulation:
+    """Simulation.
     TODO: More info.
     """
 
-    output_values: List[Number]
-    iteration: int
+    _sfg: SFG
+    _results: DefaultDict[int, Dict[str, Number]]
+    _registers: Dict[str, Number]
+    _iteration: int
+    _input_functions: Sequence[Callable[[int], Number]]
+    _current_input_values: Sequence[Number]
+    _latest_output_values: Sequence[Number]
+    _save_results: bool
 
-    def __init__(self):
-        self.output_values = []
-        self.iteration = 0
+    def __init__(self, sfg: SFG, input_providers: Optional[Sequence[Optional[InputProvider]]] = None, save_results: bool = False):
+        self._sfg = sfg
+        self._results = defaultdict(dict)
+        self._registers = {}
+        self._iteration = 0
+        self._input_functions = [
+            lambda _: 0 for _ in range(self._sfg.input_count)]
+        self._current_input_values = [0 for _ in range(self._sfg.input_count)]
+        self._latest_output_values = [0 for _ in range(self._sfg.output_count)]
+        self._save_results = save_results
+        if input_providers is not None:
+            self.set_inputs(input_providers)
 
+    def set_input(self, index: int, input_provider: InputProvider) -> None:
+        """Set the input function used to get values for the specific input at the given index to the internal SFG."""
+        if index < 0 or index >= len(self._input_functions):
+            raise IndexError(
+                f"Input index out of range (expected 0-{len(self._input_functions) - 1}, got {index})")
+        if callable(input_provider):
+            self._input_functions[index] = input_provider
+        elif isinstance(input_provider, Number):
+            self._input_functions[index] = lambda _: input_provider
+        else:
+            self._input_functions[index] = lambda n: input_provider[n]
 
-class SimulationState:
-    """Simulation state.
-    TODO: More info.
-    """
+    def set_inputs(self, input_providers: Sequence[Optional[InputProvider]]) -> None:
+        """Set the input functions used to get values for the inputs to the internal SFG."""
+        if len(input_providers) != self._sfg.input_count:
+            raise ValueError(
+                f"Wrong number of inputs supplied to simulation (expected {self._sfg.input_count}, got {len(input_providers)})")
+        self._input_functions = [None for _ in range(self._sfg.input_count)]
+        for index, input_provider in enumerate(input_providers):
+            if input_provider is not None:
+                self.set_input(index, input_provider)
+
+    @property
+    def save_results(self) -> bool:
+        """Get the flag that determines if the results of ."""
+        return self._save_results
+
+    @save_results.setter
+    def save_results(self, save_results) -> None:
+        self._save_results = save_results
+
+    def run(self) -> Sequence[Number]:
+        """Run one iteration of the simulation and return the resulting output values."""
+        return self.run_for(1)
+
+    def run_until(self, iteration: int) -> Sequence[Number]:
+        """Run the simulation until its iteration is greater than or equal to the given iteration
+        and return the resulting output values.
+        """
+        while self._iteration < iteration:
+            self._current_input_values = [self._input_functions[i](
+                self._iteration) for i in range(self._sfg.input_count)]
+            self._latest_output_values = self._sfg.evaluate_outputs(
+                self._current_input_values, self._results[self._iteration], self._registers)
+            if not self._save_results:
+                del self._results[self.iteration]
+            self._iteration += 1
+        return self._latest_output_values
+
+    def run_for(self, iterations: int) -> Sequence[Number]:
+        """Run a given number of iterations of the simulation and return the resulting output values."""
+        return self.run_until(self._iteration + iterations)
+
+    @property
+    def iteration(self) -> int:
+        """Get the current iteration number of the simulation."""
+        return self._iteration
 
-    # operation_states: Dict[OperationId, OperationState]
-    iteration: int
+    @property
+    def results(self) -> Mapping[int, OutputMap]:
+        """Get a mapping of all results, including intermediate values, calculated for each iteration up until now.
+        The outer mapping maps from iteration number to value mapping. The value mapping maps output port identifiers to values.
+        Example: {0: {"c1": 3, "c2": 4, "bfly1.0": 7, "bfly1.1": -1, "0": 7}}
+        """
+        return self._results
 
-    def __init__(self):
-        self.operation_states = {}
-        self.iteration = 0
+    def clear_results(self) -> None:
+        """Clear all results that were saved until now."""
+        self._results.clear()
 
-    # TODO: More stuff.
+    def clear_state(self) -> None:
+        """Clear all current state of the simulation, except for the results and iteration."""
+        self._registers.clear()
+        self._current_input_values = [0 for _ in range(self._sfg.input_count)]
+        self._latest_output_values = [0 for _ in range(self._sfg.output_count)]

b_asic/special_operations.py

+"""@package docstring
+B-ASIC Special Operations Module.
+TODO: More info.
+"""
+
+from numbers import Number
+from typing import Optional, Sequence
+
+from b_asic.operation import AbstractOperation, OutputKey, RegisterMap, MutableOutputMap, MutableRegisterMap
+from b_asic.graph_component import Name, TypeName
+from b_asic.port import SignalSourceProvider
+
+
+class Input(AbstractOperation):
+    """Input operation.
+    TODO: More info.
+    """
+
+    def __init__(self, name: Name = ""):
+        super().__init__(input_count=0, output_count=1, name=name)
+        self.set_param("value", 0)
+
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "in"
+
+    def evaluate(self):
+        return self.param("value")
+
+    @property
+    def value(self) -> Number:
+        """Get the current value of this input."""
+        return self.param("value")
+
+    @value.setter
+    def value(self, value: Number) -> None:
+        """Set the current value of this input."""
+        self.set_param("value", value)
+
+
+class Output(AbstractOperation):
+    """Output operation.
+    TODO: More info.
+    """
+
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, name: Name = ""):
+        super().__init__(input_count=1, output_count=0,
+                         name=name, input_sources=[src0])
+
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "out"
+
+    def evaluate(self, _):
+        return None
+
+
+class Register(AbstractOperation):
+    """Unit delay operation.
+    TODO: More info.
+    """
+
+    def __init__(self, src0: Optional[SignalSourceProvider] = None, initial_value: Number = 0, name: Name = ""):
+        super().__init__(input_count=1, output_count=1,
+                         name=name, input_sources=[src0])
+        self.set_param("initial_value", initial_value)
+
+    @classmethod
+    def type_name(cls) -> TypeName:
+        return "reg"
+
+    def evaluate(self, a):
+        return self.param("initial_value")
+
+    def current_output(self, index: int, registers: Optional[RegisterMap] = None, prefix: str = "") -> Optional[Number]:
+        if registers is not None:
+            return registers.get(self.key(index, prefix), self.param("initial_value"))
+        return self.param("initial_value")
+
+    def evaluate_output(self, index: int, input_values: Sequence[Number], results: Optional[MutableOutputMap] = None, registers: Optional[MutableRegisterMap] = None, prefix: str = "") -> Number:
+        if index != 0:
+            raise IndexError(
+                f"Output index out of range (expected 0-0, got {index})")
+        if len(input_values) != 1:
+            raise ValueError(
+                f"Wrong number of inputs supplied to SFG for evaluation (expected 1, got {len(input_values)})")
+
+        key = self.key(index, prefix)
+        value = self.param("initial_value")
+        if registers is not None:
+            value = registers.get(key, value)
+            registers[key] = self.truncate_inputs(input_values)[0]
+        if results is not None:
+            results[key] = value
+        return value

src/main.cpp

-#include <pybind11/pybind11.h>
-
-namespace py = pybind11;
-
-namespace asic {
-
-int add(int a, int b) {
-	return a + b;
-}
-
-int sub(int a, int b) {
-	return a - b;
-}
-
-} // namespace asic
-
-PYBIND11_MODULE(_b_asic, m) {
-	m.doc() = "Better ASIC Toolbox Extension Module.";
-	m.def("add", &asic::add, "A function which adds two numbers.", py::arg("a"), py::arg("b"));
-	m.def("sub", &asic::sub, "A function which subtracts two numbers.", py::arg("a"), py::arg("b"));
+#include <pybind11/pybind11.h>
+
+namespace py = pybind11;
+
+namespace asic {
+
+int add(int a, int b) {
+	return a + b;
+}
+
+int sub(int a, int b) {
+	return a - b;
+}
+
+} // namespace asic
+
+PYBIND11_MODULE(_b_asic, m) {
+	m.doc() = "Better ASIC Toolbox Extension Module.";
+	m.def("add", &asic::add, "A function which adds two numbers.", py::arg("a"), py::arg("b"));
+	m.def("sub", &asic::sub, "A function which subtracts two numbers.", py::arg("a"), py::arg("b"));
 }
\ No newline at end of file

test/conftest.py

 from test.fixtures.signal import signal, signals
 from test.fixtures.operation_tree import *
 from test.fixtures.port import *
+from test.fixtures.signal_flow_graph import *
 import pytest

test/fixtures/operation_tree.py

-from b_asic.core_operations import Addition, Constant
-from b_asic.signal import Signal
-
 import pytest
 
+from b_asic import Addition, Constant, Signal, Butterfly
+
+
 @pytest.fixture
 def operation():
     return Constant(2)
 
-def create_operation(_type, dest_oper, index, **kwargs):
-    oper = _type(**kwargs)
-    oper_signal = Signal()
-    oper._output_ports[0].add_signal(oper_signal)
-
-    dest_oper._input_ports[index].add_signal(oper_signal)
-    return oper
-
 @pytest.fixture
 def operation_tree():
-    """Return a addition operation connected with 2 constants.
-    ---C---+
-           ---A
-    ---C---+
+    """Valid addition operation connected with 2 constants.
+    2---+
+        |
+        v
+       add = 2 + 3 = 5
+        ^
+        |
+    3---+
     """
-    add_oper = Addition()
-    create_operation(Constant, add_oper, 0, value=2)
-    create_operation(Constant, add_oper, 1, value=3)
-    return add_oper
+    return Addition(Constant(2), Constant(3))
 
 @pytest.fixture
 def large_operation_tree():
-    """Return a constant operation connected with a large operation tree with 3 other constants and 3 additions.
-    ---C---+
-           ---A---+
-    ---C---+      |
-                  +---A
-    ---C---+      |
-           ---A---+
-    ---C---+
+    """Valid addition operation connected with a large operation tree with 2 other additions and 4 constants.
+    2---+
+        |
+        v
+       add---+
+        ^    |
+        |    |
+    3---+    v
+            add = (2 + 3) + (4 + 5) = 14
+    4---+    ^
+        |    |
+        v    |
+       add---+
+        ^
+        |
+    5---+
     """
-    add_oper = Addition()
-    add_oper_2 = Addition()
-
-    const_oper = create_operation(Constant, add_oper, 0, value=2)
-    create_operation(Constant, add_oper, 1, value=3)
+    return Addition(Addition(Constant(2), Constant(3)), Addition(Constant(4), Constant(5)))
 
-    create_operation(Constant, add_oper_2, 0, value=4)
-    create_operation(Constant, add_oper_2, 1, value=5)
+@pytest.fixture
+def large_operation_tree_names():
+    """Valid addition operation connected with a large operation tree with 2 other additions and 4 constants.
+    With names.
+    2---+
+        |
+        v
+       add---+
+        ^    |
+        |    |
+    3---+    v
+            add = (2 + 3) + (4 + 5) = 14
+    4---+    ^
+        |    |
+        v    |
+       add---+
+        ^
+        |
+    5---+
+    """
+    return Addition(Addition(Constant(2, name="constant2"), Constant(3, name="constant3")), Addition(Constant(4, name="constant4"), Constant(5, name="constant5")))
 
-    add_oper_3 = Addition()
-    add_oper_signal = Signal(add_oper.output(0), add_oper_3.output(0))
-    add_oper._output_ports[0].add_signal(add_oper_signal)
-    add_oper_3._input_ports[0].add_signal(add_oper_signal)
+@pytest.fixture
+def butterfly_operation_tree():
+    """Valid butterfly operations connected to eachother with 3 butterfly operations and 2 constants as inputs and 2 outputs.
+    2 ---+       +--- (2 + 4) ---+       +--- (6 + (-2)) ---+       +--- (4 + 8) ---> out1 = 12
+         |       |               |       |                  |       |
+         v       ^               v       ^                  v       ^
+         butterfly               butterfly                  butterfly
+         ^       v               ^       v                  ^       v
+         |       |               |       |                  |       |               
+    4 ---+       +--- (2 - 4) ---+       +--- (6 - (-2)) ---+       +--- (4 - 8) ---> out2 = -4
+    """
+    return Butterfly(*(Butterfly(*(Butterfly(Constant(2), Constant(4), name="bfly3").outputs), name="bfly2").outputs), name="bfly1")
 
-    add_oper_2_signal = Signal(add_oper_2.output(0), add_oper_3.output(0))
-    add_oper_2._output_ports[0].add_signal(add_oper_2_signal)
-    add_oper_3._input_ports[1].add_signal(add_oper_2_signal)
-    return const_oper
+@pytest.fixture
+def operation_graph_with_cycle():
+    """Invalid addition operation connected with an operation graph containing a cycle.
+     +-+
+     | |
+     v |
+    add+---+
+     ^     |
+     |     v
+     7    add = (? + 7) + 6 = ?
+           ^
+           |
+           6
+    """
+    add1 = Addition(None, Constant(7))
+    add1.input(0).connect(add1)
+    return Addition(add1, Constant(6))

test/fixtures/port.py

 import pytest
-from b_asic.port import InputPort, OutputPort
+
+from b_asic import InputPort, OutputPort
+
 
 @pytest.fixture
 def input_port():
-    return InputPort(0, None)
+    return InputPort(None, 0)
 
 @pytest.fixture
 def output_port():
-    return OutputPort(0, None)
+    return OutputPort(None, 0)
+
+@pytest.fixture
+def list_of_input_ports():
+    return [InputPort(None, i) for i in range(0, 3)]
+
+@pytest.fixture
+def list_of_output_ports():
+    return [OutputPort(None, i) for i in range(0, 3)]