双向rrt算法python代码

以下是双向RRT算法的Python代码示例：

import random
import math
import matplotlib.pyplot as plt

class RRTNode:
    def __init__(self, x, y):
        self.x = x
        self.y = y
        self.parent = None

class BiRRT:
    def __init__(self, start, goal, obstacle_list, rand_area, expand_dist=0.5, goal_sample_rate=20, max_iter=500):
        self.start_node = RRTNode(start[0], start[1])
        self.goal_node = RRTNode(goal[0], goal[1])
        self.obstacle_list = obstacle_list
        self.min_rand = rand_area[0]
        self.max_rand = rand_area[1]
        self.expand_dist = expand_dist
        self.goal_sample_rate = goal_sample_rate
        self.max_iter = max_iter
        self.node_list1 = [self.start_node]
        self.node_list2 = [self.goal_node]
        self.path = []

    def planning(self):
        for i in range(self.max_iter):
            if random.randint(0, 100) > self.goal_sample_rate:
                rnd = self.get_random_node()
            else:
                rnd = self.goal_node
            nearest_node1 = self.nearest_node(self.node_list1, rnd)
            nearest_node2 = self.nearest_node(self.node_list2, rnd)
            new_node1 = self.steer(nearest_node1, rnd, self.expand_dist)
            new_node2 = self.steer(nearest_node2, rnd, self.expand_dist)
            if self.check_collision(new_node1) and self.check_collision(new_node2):
                self.node_list1.append(new_node1)
                self.node_list2.append(new_node2)
                self.connect(new_node1, new_node2)
                if self.calc_dist(new_node1, self.goal_node) < self.expand_dist:
                    final_node = self.steer(new_node1, self.goal_node, self.expand_dist)
                    if self.check_collision(final_node):
                        self.path = self.get_path(final_node)
                        return self.path
            self.node_list1, self.node_list2 = self.node_list2, self.node_list1

    def steer(self, from_node, to_node, extend_length=float("inf")):
        new_node = RRTNode(from_node.x, from_node.y)
        dist, angle = self.calc_distance_and_angle(new_node, to_node)
        if dist < extend_length:
            extend_length = dist
        new_node.x += extend_length * math.cos(angle)
        new_node.y += extend_length * math.sin(angle)
        new_node.parent = from_node
        return new_node

    def connect(self, from_node, to_node):
        from_node.parent = to_node

    def get_path(self, node):
        path = [[node.x, node.y]]
        while node.parent:
            node = node.parent
            path.append([node.x, node.y])
        return path

    def nearest_node(self, node_list, node):
        nearest_node = node_list[0]
        for n in node_list:
            if self.calc_dist(n, node) < self.calc_dist(nearest_node, node):
                nearest_node = n
        return nearest_node

    def calc_dist(self, from_node, to_node):
        return math.sqrt((from_node.x - to_node.x) ** 2 + (from_node.y - to_node.y) ** 2)

    def calc_distance_and_angle(self, from_node, to_node):
        dx = to_node.x - from_node.x
        dy = to_node.y - from_node.y
        dist = math.sqrt(dx ** 2 + dy ** 2)
        angle = math.atan2(dy, dx)
        return dist, angle

    def check_collision(self, node):
        for (ox, oy, size) in self.obstacle_list:
            if math.sqrt((node.x - ox) ** 2 + (node.y - oy) ** 2) <= size:
                return False
        return True

    def get_random_node(self):
        if random.randint(0, 100) > self.goal_sample_rate:
            rnd = RRTNode(random.uniform(self.min_rand, self.max_rand), random.uniform(self.min_rand, self.max_rand))
        else:
            rnd = self.goal_node
        return rnd

    def plot_path(self):
        plt.plot([x for (x, y) in self.path], [y for (x, y) in self.path], '-r')
        for (ox, oy, size) in obstacleList:
            circle = plt.Circle((ox, oy), size, color='b')
            plt.gcf().gca().add_artist(circle)
        plt.plot(self.start_node.x, self.start_node.y, 'xr')
        plt.plot(self.goal_node.x, self.goal_node.y, 'xr')
        plt.axis('equal')
        plt.show()

if __name__ == '__main__':
    obstacleList = [(5, 5, 1), (3, 6, 2), (3, 8, 2), (5, 10, 2), (7, 9, 2), (9, 10, 2)]
    start = [0.0, 0.0]
    goal = [10.0, 10.0]
    rrt = BiRRT(start, goal, obstacleList, [-2, 12])
    path = rrt.planning()
    if path:
        print(path)
        rrt.plot_path()
    else:
        print("Cannot find path!") 

请注意，此示例仅用于演示双向RRT算法，并且可能需要根据您的具体需求进行修改。