mirror of
https://github.com/zhm-real/PathPlanning.git
synced 2026-08-29 16:40:46 +08:00
zhm-real
120 lines
3.2 KiB
Python
120 lines
3.2 KiB
Python
"""
|
|
Depth-first Searching_2D (DFS)
|
|
@author: huiming zhou
|
|
"""
|
|
|
|
import os
|
|
import sys
|
|
from collections import deque
|
|
|
|
sys.path.append(os.path.dirname(os.path.abspath(__file__)) +
|
|
"/../../Search_based_Planning/")
|
|
|
|
from Search_based_Planning.Search_2D import plotting, env
|
|
|
|
|
|
class DFS:
|
|
def __init__(self, s_start, s_goal):
|
|
self.s_start = s_start
|
|
self.s_goal = s_goal
|
|
|
|
self.Env = env.Env()
|
|
self.plotting = plotting.Plotting(self.s_start, self.s_goal)
|
|
|
|
self.u_set = self.Env.motions # feasible input set
|
|
self.obs = self.Env.obs # position of obstacles
|
|
|
|
self.OPEN = deque() # OPEN set: visited nodes
|
|
self.PARENT = dict() # recorded parent
|
|
self.CLOSED = [] # CLOSED set / visited order
|
|
|
|
def searching(self):
|
|
"""
|
|
Depth-first Searching
|
|
:return: planning path, visited order
|
|
"""
|
|
|
|
self.PARENT[self.s_start] = self.s_start
|
|
self.OPEN.append(self.s_start)
|
|
|
|
while self.OPEN:
|
|
s = self.OPEN.pop()
|
|
|
|
if s == self.s_goal:
|
|
break
|
|
self.CLOSED.append(s)
|
|
|
|
for s_n in self.get_neighbor(s):
|
|
if self.is_collision(s, s_n):
|
|
continue
|
|
if s_n not in self.PARENT: # node not explored
|
|
self.OPEN.append(s_n)
|
|
self.PARENT[s_n] = s
|
|
|
|
return self.extract_path(), self.CLOSED
|
|
|
|
def get_neighbor(self, s):
|
|
"""
|
|
find neighbors of state s that not in obstacles.
|
|
:param s: state
|
|
:return: neighbors : [nodes]
|
|
"""
|
|
|
|
return [(s[0] + u[0], s[1] + u[1]) for u in self.u_set]
|
|
|
|
def is_collision(self, s_start, s_end):
|
|
"""
|
|
check if the line segment (s_start, s_end) is collision.
|
|
:param s_start: start node
|
|
:param s_end: end node
|
|
:return: True: is collision / False: not collision
|
|
"""
|
|
|
|
if s_start in self.obs or s_end in self.obs:
|
|
return True
|
|
|
|
if s_start[0] != s_end[0] and s_start[1] != s_end[1]:
|
|
if s_end[0] - s_start[0] == s_start[1] - s_end[1]:
|
|
s1 = (min(s_start[0], s_end[0]), min(s_start[1], s_end[1]))
|
|
s2 = (max(s_start[0], s_end[0]), max(s_start[1], s_end[1]))
|
|
else:
|
|
s1 = (min(s_start[0], s_end[0]), max(s_start[1], s_end[1]))
|
|
s2 = (max(s_start[0], s_end[0]), min(s_start[1], s_end[1]))
|
|
|
|
if s1 in self.obs or s2 in self.obs:
|
|
return True
|
|
|
|
return False
|
|
|
|
def extract_path(self):
|
|
"""
|
|
Extract the path based on the relationship of nodes.
|
|
:return: The planning path
|
|
"""
|
|
|
|
path = [self.s_goal]
|
|
s = self.s_goal
|
|
|
|
while True:
|
|
s = self.PARENT[s]
|
|
path.append(s)
|
|
if s == self.s_start:
|
|
break
|
|
|
|
return list(path)
|
|
|
|
|
|
def main():
|
|
s_start = (5, 5)
|
|
s_goal = (45, 25)
|
|
|
|
dfs = DFS(s_start, s_goal)
|
|
plot = plotting.Plotting(s_start, s_goal)
|
|
|
|
path, visited = dfs.searching()
|
|
plot.animation(path, visited, "Depth-first Searching (DFS)") # animation
|
|
|
|
|
|
if __name__ == '__main__':
|
|
main()
|