Initial commit

TravellingSalesman.py

+import matplotlib.pyplot as plt
+from math import *
+from random import randint
+from string import ascii_uppercase
+from itertools import permutations
+# config:
+brute_force = True
+num_nodes = 9
+do_plot = True
+pause = 1
+
+class Node:
+    x: int
+    y: int
+    name: str
+    def __init__(self, x: int, y: int, name: str):
+        self.x = x
+        self.y = y
+        self.name = name
+    
+    def plot(this):
+        plt.plot(this.x, this.y, 'ro', label=this.name)
+
+def distance(A: Node, B: Node) -> float:
+    return sqrt((A.x - B.x)**2 + (A.y - B.y)**2)
+
+def total_distance(route: list) -> float:
+    total_distance = 0
+    for i in range(len(route)):
+        if i == len(route)-1:
+            total_distance += distance(route[i], route[0])
+        else:
+            total_distance += distance(route[i], route[i+1])
+    return total_distance
+
+class Path:
+    A: Node
+    B: Node
+    distance: float
+    def __init__(self, A: Node, B: Node):
+        self.A = A
+        self.B = B
+        #self.distance = distance(A, B)
+    
+    def plot(this):
+        plt.plot([this.A.x, this.B.x], [this.A.y, this.B.y], 'go-')
+
+
+def plot_route(route: list) -> None:
+    plt.close("all")
+    for i in range(len(route)):
+        if i == len(route) - 1:
+            Path(A=route[i], B=route[0]).plot()
+        else:
+            Path(A=route[i], B=route[i+1]).plot()
+    plt.show()
+    plt.pause(pause)
+
+
+def brute(nodes: list):
+    if len(nodes) <= 1:
+        return
+    best_route = nodes
+    best_route_length = total_distance(nodes)
+    if do_plot:
+        plot_route(best_route)
+    for i, route in enumerate(permutations(nodes, len(nodes))):
+        route_length = total_distance(route)
+        if route_length < best_route_length:
+            best_route = route
+            best_route_length = route_length
+            print("Found shorter Route with length " + str(best_route_length) + " after " +  str(i) + " iterations.")
+            if do_plot:
+                plot_route(best_route)
+    print(str(i+1) + " iterations in total")
+    return best_route
+
+
+def generate_paths(nodes: list) -> list:
+    _nodes = nodes.copy()
+    paths = []
+    if _nodes.__len__() <= 1:
+        return []
+
+    this_node = _nodes[0]
+    _nodes.remove(_nodes[0])
+    
+    for node in _nodes:
+        paths.append(Path(A=this_node, B=node))
+    
+    if _nodes.__len__() >= 2:
+        paths = paths + generate_paths(_nodes)
+    
+    return paths
+
+
+
+if __name__ == "__main__":
+    nodes = []
+    for i in range(num_nodes):
+        nodes.append(Node(x=randint(0, 100), y=randint(0, 100), name=ascii_uppercase[i]))
+        
+
+    plt.ion()
+    
+    best_route = brute(nodes)
+    
+    plot_route(best_route)
+    plt.show(block=True)