我正在编写一个简单的蒙特卡罗模拟脚本,稍后将对其进行扩展以用于一个更大的项目。该脚本是一个基本的爬虫程序,试图在一个网格中从点A到点B移动。点A的坐标为(1,1)(即左上角),点B的坐标为(n,n)(即右下角,其中n是网格的大小)。
一旦爬行者开始移动,就有四个选项,可以向左、向右、向上或向下移动(不允许对角线运动)。如果这四个选项中的任何一个满足以下条件:
我想运行100万次模拟(下面的代码仅运行100次),每次迭代应终止:
我打赌我错过了什么简单的东西,但出于某种原因看不到它。有什么想法吗?
非常感谢!
注:文本中有一些笔误已更正。
一旦爬行者开始移动,就有四个选项,可以向左、向右、向上或向下移动(不允许对角线运动)。如果这四个选项中的任何一个满足以下条件:
- 新点仍应位于n x n网格的边界内
- 新点不应被先前访问过
我想运行100万次模拟(下面的代码仅运行100次),每次迭代应终止:
- 爬行者被困住了(没有有效的移动选项)
- 爬行者到达网格的最终目的地(n,n)。
我打赌我错过了什么简单的东西,但出于某种原因看不到它。有什么想法吗?
非常感谢!
注:文本中有一些笔误已更正。
import random
i = 1 # initial coordinate top left corner
j = 1 # initial coordinate top left corner
k = 0 # counter for number of simulations
n = 3 # Grid size
foundRoute = 0 # counter for number of cases where the final point is reached
gotStuck = 0 # counter for number of cases where no valid options found
coordList = [[i, j]]
while k < 100:
while True:
validOptions = []
opt1 = [i - 1, j]
opt2 = [i, j + 1]
opt3 = [i + 1, j]
opt4 = [i, j - 1]
# Check 4 possible options out of bound and re-visited coordinates are
# discarded:
if opt1[0] != 0 and opt1[0] <= n and opt1[1] != 0 and opt1[1] <= n:
if not opt1 in coordList:
validOptions.append(opt1)
if opt2[0] != 0 and opt2[0] <= n and opt2[1] != 0 and opt2[1] <= n:
if not opt2 in coordList:
validOptions.append(opt2)
if opt3[0] != 0 and opt3[0] <= n and opt3[1] != 0 and opt3[1] <= n:
if not opt3 in coordList:
validOptions.append(opt3)
if opt4[0] != 0 and opt4[0] <= n and opt4[1] != 0 and opt4[1] <= n:
if not opt4 in coordList:
validOptions.append(opt4)
# Break loop if there are no valid options
if len(validOptions) == 0:
gotStuck = gotStuck + 1
break
# Get random coordinate among current valid options
newCoord = random.choice(validOptions)
# Append new coordinate to the list of grid points visited (to be used
# for checks)
coordList.append(newCoord)
# Break loop if lower right corner of the grid is reached
if newCoord == [n, n]:
foundRoute = foundRoute + 1
break
# If the loop is not broken, assign new coordinates
i = newCoord[0]
j = newCoord[1]
k = k + 1
print 'Route found %i times' % foundRoute
print 'Route not found %i times' % gotStuck
while
循环放在了后面,搞砸了。看来我需要再喝杯咖啡......非常感谢! - marillion