first commit

DESCRIPTION

+Package: exercise
+Type: Package
+Title: Lab 3 exercise
+Version: 1.0
+Date: 2024-09-12
+Author:Liuxi Mei
+Maintainer: Liuxi Mei <liume102@student.liu.se>
+Description: This is a exercise for lab 3.
+License: GPL (>= 2)
+RoxygenNote: 7.3.2
+Encoding: UTF-8

NAMESPACE

+# Generated by roxygen2: do not edit by hand
+

R/lab_3_submission.R

+
+
+#' Euclidian algorithm to find the 
+#' greatest common divisor of two numbers
+#' @title  euclidean algorithm
+#' @param x first number
+#' @param y second number
+
+euclidean <- function(x,y) {
+  if (!is.numeric(x) | length(x) != 1){
+    stop('pls check your input x')
+  }
+  if (!is.numeric(y) | length(y) != 1){
+    stop('pls check your input y')
+  }
+  a <- ifelse(x < y, y, x)
+  b <- ifelse(x < y, x, y)
+  repeat{
+    mode = a %% b
+    if (mode == 0) {
+      return (b)
+    }
+    a <- b
+    b <- mode
+  }
+  return (b)
+}
+
+
+#' @description init the detail table
+#' @title  initial the detail frame 
+#' @param init_node the start node to find the shortest path
+#' @param graph the structure of the graph,
+#' eg:wiki_graph <- data.frame(v1=c(1,1,1,2,2,2,3,3,3,3,4,4,4,5,5,6,6,6),
+#'            v2=c(2,3,6,1,3,4,1,2,4,6,2,3,5,4,6,1,3,5),
+#'             w=c(7,9,14,7,10,15,9,10,11,2,15,11,6,6,9,14,2,9))
+init_node_distance_list <- function (init_node, graph) {
+  node_distance_list <- list(init_node = 0)
+  # first, get all unqiue nodes 
+  all_nodes <- unique(append(graph[,'v1'],graph[,'v2']))
+  detail_frame <- data.frame(matrix(ncol=length(all_nodes),nrow = 3))
+  names(detail_frame) <- all_nodes
+  row.names(detail_frame) <- c('is_best_node','node_distance','previous_node')
+  detail_frame['node_distance', ]<- Inf
+  detail_frame['node_distance',init_node] <- 0
+  detail_frame['is_best_node',init_node] <- TRUE
+  checked_nodes <- list(init_node)
+  unchecked_nodes <- all_nodes[-which( all_nodes == init_node)]
+  return (list(detail_frame=detail_frame, checked_nodes=checked_nodes, unchecked_nodes=unchecked_nodes))
+}
+
+
+#' @description
+#' the update method for detail table to record the shortest path
+#' @title update the detail frame when traversing to a new node
+#' @param node the current the node when traversing all the nodes to find the best way
+#' @param init_node the start node in the algorithm
+#' @param checked_nodes the nodes that having found the shortest path
+#' @param unchecked_nodes the nodes that having not found the shortest path
+
+update_detail_path <- function(node,init_node,detail_frame,graph,checked_nodes,unchecked_nodes) {
+  #get connected nodes to node
+  if (length(unchecked_nodes) == 0){
+    # browser() 
+    return (detail_frame)
+  }
+  connected_nodes <- graph[graph$v1 == node,]$v2
+  next_node <- NULL
+  min_path <- Inf
+  for (c_node in connected_nodes){
+    current_distance <- graph[graph$v1 == node & graph$v2 == c_node,]$w 
+    if (node == init_node) {
+      detail_frame['node_distance',c_node] <- current_distance
+      detail_frame['previous_node',c_node] <- init_node
+      if(current_distance < min_path) {
+        min_path <- current_distance
+        next_node <- c_node
+        # detail_frame['best_node',c_node] <-TRUE
+      }
+    }else{
+      # browser() 
+      if (c_node %in% checked_nodes) next
+      
+      previous_distance <- detail_frame['node_distance',node] 
+      source_distance <-  previous_distance + current_distance
+      exist_distance <- detail_frame['node_distance',c_node]
+      #差更新前置节点
+      if (source_distance < exist_distance) {
+        
+        # update source distance
+        detail_frame['node_distance',c_node] <- source_distance
+        # update previous node
+        detail_frame['previous_node',c_node] <- node
+      }else{
+        source_distance <- exist_distance
+      }
+      if (source_distance < min_path) {
+        min_path <- source_distance
+        next_node <- c_node
+      }
+    }
+  }
+  
+  checked_nodes <- append(checked_nodes,next_node)
+  unchecked_nodes <- unchecked_nodes[-which(unchecked_nodes==next_node)]
+  detail_frame['is_best_node',next_node] <-TRUE
+  return (update_detail_path(next_node,init_node,detail_frame,graph,checked_nodes,unchecked_nodes))
+}
+
+#' @description
+#' the dijkstra algorithm to find the shortest path in the graph
+#' @title the entrance of the dijkstra algorithm
+#' @param graph a graph to find the shortest path 
+#' @param init_node the start node to find the shortest path in the graph 
+dijkstra <- function(graph, init_node) {
+  
+  res<- init_node_distance_list(init_node,graph)
+  detail_frame <- res$detail_frame
+  checked_nodes <- res$checked_nodes
+  unchecked_nodes <- res$unchecked_nodes
+  updated_detail_frame <- update_detail_path(init_node,init_node,detail_frame,graph,checked_nodes,unchecked_nodes)
+  return (unname(unlist(updated_detail_frame['node_distance',])))
+}
+  
+  
+  
+  
+  

exercise.Rproj

+Version: 1.0
+
+RestoreWorkspace: Default
+SaveWorkspace: Default
+AlwaysSaveHistory: Default
+
+EnableCodeIndexing: Yes
+UseSpacesForTab: Yes
+NumSpacesForTab: 2
+Encoding: UTF-8
+
+RnwWeave: Sweave
+LaTeX: pdfLaTeX
+
+BuildType: Package
+PackageUseDevtools: Yes
+PackagePath: /Users/meiliuxi/Advanced_R/exercise
+PackageInstallArgs: --no-multiarch --with-keep.source
+PackageRoxygenize: rd,collate,namespace,vignette

man/dijkstra.Rd

+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/lab_3_submission.R
+\name{dijkstra}
+\alias{dijkstra}
+\title{the entrance of the dijkstra algorithm}
+\usage{
+dijkstra(graph, init_node)
+}
+\arguments{
+\item{graph}{a graph to find the shortest path}
+
+\item{init_node}{the start node to find the shortest path in the graph}
+}
+\description{
+the dijkstra algorithm to find the shortest path in the graph
+}

man/euclidean.Rd

+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/lab_3_submission.R
+\name{euclidean}
+\alias{euclidean}
+\title{euclidean algorithm}
+\usage{
+euclidean(x, y)
+}
+\arguments{
+\item{x}{first number}
+
+\item{y}{second number}
+}
+\description{
+Euclidian algorithm to find the 
+greatest common divisor of two numbers
+}

man/init_node_distance_list.Rd

+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/lab_3_submission.R
+\name{init_node_distance_list}
+\alias{init_node_distance_list}
+\title{initial the detail frame}
+\usage{
+init_node_distance_list(init_node, graph)
+}
+\arguments{
+\item{init_node}{the start node to find the shortest path}
+
+\item{graph}{the structure of the graph,
+eg:wiki_graph <- data.frame(v1=c(1,1,1,2,2,2,3,3,3,3,4,4,4,5,5,6,6,6),
+           v2=c(2,3,6,1,3,4,1,2,4,6,2,3,5,4,6,1,3,5),
+            w=c(7,9,14,7,10,15,9,10,11,2,15,11,6,6,9,14,2,9))}
+}
+\description{
+init the detail table
+}

man/update_detail_path.Rd

+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/lab_3_submission.R
+\name{update_detail_path}
+\alias{update_detail_path}
+\title{update the detail frame when traversing to a new node}
+\usage{
+update_detail_path(
+  node,
+  init_node,
+  detail_frame,
+  graph,
+  checked_nodes,
+  unchecked_nodes
+)
+}
+\arguments{
+\item{node}{the current the node when traversing all the nodes to find the best way}
+
+\item{init_node}{the start node in the algorithm}
+
+\item{checked_nodes}{the nodes that having found the shortest path}
+
+\item{unchecked_nodes}{the nodes that having not found the shortest path}
+}
+\description{
+the update method for detail table to record the shortest path
+}