Created
November 23, 2015 08:19
-
-
Save mezentsev/97026f2d53116d26210b to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import numpy | |
from heapq import * | |
def heuristic(a, b): | |
return (b[0] - a[0]) ** 2 + (b[1] - a[1]) ** 2 | |
def astar(array, start, goal): | |
neighbors = [(0,1),(0,-1),(1,0),(-1,0),(1,1),(1,-1),(-1,1),(-1,-1)] | |
close_set = set() | |
came_from = {} | |
gscore = {start:0} | |
fscore = {start:heuristic(start, goal)} | |
oheap = [] | |
heappush(oheap, (fscore[start], start)) | |
while oheap: | |
current = heappop(oheap)[1] | |
if current == goal: | |
data = [] | |
while current in came_from: | |
data.append(current) | |
current = came_from[current] | |
return data | |
close_set.add(current) | |
for i, j in neighbors: | |
neighbor = current[0] + i, current[1] + j | |
tentative_g_score = gscore[current] + heuristic(current, neighbor) | |
if 0 <= neighbor[0] < array.shape[0]: | |
if 0 <= neighbor[1] < array.shape[1]: | |
if array[neighbor[0]][neighbor[1]] == 1: | |
continue | |
else: | |
# array bound y walls | |
continue | |
else: | |
# array bound x walls | |
continue | |
if neighbor in close_set and tentative_g_score >= gscore.get(neighbor, 0): | |
continue | |
if tentative_g_score < gscore.get(neighbor, 0) or neighbor not in [i[1]for i in oheap]: | |
came_from[neighbor] = current | |
gscore[neighbor] = tentative_g_score | |
fscore[neighbor] = tentative_g_score + heuristic(neighbor, goal) | |
heappush(oheap, (fscore[neighbor], neighbor)) | |
return False | |
'''Here is an example of using my algo with a numpy array, | |
astar(array, start, destination) | |
astar function returns a list of points (shortest path)''' | |
nmap = numpy.array([ | |
[0,0,0,0,0,0,0,0,0,0,0,0,0,0], | |
[1,1,1,1,1,1,1,1,1,1,1,1,0,1], | |
[0,0,0,0,0,0,0,0,0,0,0,0,0,0], | |
[1,0,1,1,1,1,1,1,1,1,1,1,1,1], | |
[0,0,0,0,0,0,0,0,0,0,0,0,0,0], | |
[1,1,1,1,1,1,1,1,1,1,1,1,0,1], | |
[0,0,0,0,0,0,0,0,0,0,0,0,0,0], | |
[1,0,1,1,1,1,1,1,1,1,1,1,1,1], | |
[0,0,0,0,0,0,0,0,0,0,0,0,0,0], | |
[1,1,1,1,1,1,1,1,1,1,1,1,0,1], | |
[0,0,0,0,0,0,0,0,0,0,0,0,0,0]]) | |
print astar(nmap, (0,0), (10,13)) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment