我想使用 cython 的高效索引功能使一些代码更快:http://docs.cython.org/src/tutorial/numpy.html
基本上,代码表示按钮对游戏游戏板的依赖性 http://www.hacker.org/cross/index.php
# file test_so_cy.pyx
import time
import numpy as np
cimport numpy as np
DTYPE = np.uint8
ctypedef np.uint8_t DTYPE_t
def time_fmt(td):
return "{:.2f} s".format(td)
def derive_equations(np.ndarray[DTYPE_t, ndim=2] field not None):
cdef unsigned int n, m, i, j, x, y
t1 = time.time()
n, m = len(field), len(field[0])
# generate equations for dimensions n and m
eqs = []
block = 2 # as soon as a 2 is hit there isnt any influence
for i in xrange(n):
for j in xrange(m):
eq = 0L
if field[i][j] == block:
eqs.append([i*m+j ,field[i][j], eq])
continue
# rows upwards
for x in xrange(i-1, -1, -1):
if field[x][j] == block: break
eq ^= 1L << (x*m+j)
# rows downwards
for x in xrange(i, n):
if field[x][j] == block: break
eq ^= 1L << (x*m+j)
# cols left
for y in xrange(j-1, -1, -1):
if field[i][y] == block: break
eq ^= 1L << (i*m+y)
# cols right
# j+1 to avoid resetting the influence of itself
for y in xrange(j+1, m):
if field[i][y] == block: break
eq ^= 1L << (i*m+y)
eqs.append([i*m+j, field[i][j], eq])
t2 = time.time()
print 'preprocess time:', time_fmt(t2 - t1)
return n, m, eqs
def main():
field = np.array(
[[0,1,0,0,0,0,0,0,0,0,0,1,1,1,0,2,1,0,0,2,1,0,1,1,0,0,0,0,0],
[0,1,0,0,1,1,0,1,0,0,0,1,1,0,0,1,0,1,0,0,1,0,1,1,1,0,1,1,1],
[1,1,0,1,0,0,0,0,0,0,0,1,1,0,1,0,1,0,0,1,0,1,1,0,0,1,0,0,2],
[0,0,0,0,1,0,1,1,0,1,1,1,0,1,0,1,1,0,0,0,1,1,0,0,2,1,1,0,1],
[0,1,0,1,1,1,1,1,2,1,1,0,1,0,0,0,0,0,0,1,0,0,1,0,2,0,1,0,1],
[0,1,1,0,0,1,1,0,1,0,0,1,1,1,0,1,1,1,0,0,1,1,1,0,1,0,1,1,1],
[0,0,0,1,0,1,1,0,1,0,0,1,1,1,0,1,0,0,0,0,0,0,0,1,0,1,0,1,1],
[1,0,1,0,1,1,0,0,0,0,0,1,0,0,2,0,1,1,0,0,0,0,1,0,0,2,1,0,0],
[1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,1,0,1,1,0,1,0,1,0,1,0,1,1,1],
[0,0,1,0,0,1,1,0,1,0,0,1,0,0,1,0,0,0,1,0,0,0,0,1,0,1,1,1,2],
[1,0,1,1,0,0,1,0,1,1,1,0,1,2,1,1,1,2,1,0,1,1,1,0,0,0,0,0,0],
[0,0,1,0,1,0,0,1,0,1,1,1,1,1,1,0,0,1,1,0,0,1,0,0,0,1,0,0,1],
[1,1,0,0,0,1,0,0,1,0,0,1,0,1,1,0,0,0,0,1,1,0,0,1,0,0,0,0,0],
[1,1,1,0,1,1,1,1,0,0,1,0,1,1,0,0,0,0,1,1,1,1,1,0,1,0,1,0,1],
[1,0,0,0,1,1,0,0,2,0,1,1,2,0,0,1,0,1,0,1,0,2,1,1,1,1,0,0,2],
[1,0,1,1,1,1,1,0,0,1,1,0,1,1,0,0,1,0,0,0,2,1,0,1,0,1,0,1,1],
[0,0,1,1,1,0,0,0,0,0,2,1,0,1,0,1,0,1,1,1,1,0,0,1,1,1,1,0,1],
[0,1,0,1,2,0,0,0,0,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,1,0,1,1,0],
[0,1,0,0,2,0,0,0,1,0,1,0,0,1,0,1,1,0,0,1,0,1,1,1,0,1,1,1,1],
[1,0,0,1,0,0,1,0,1,0,0,2,0,1,1,1,1,1,0,0,1,0,1,0,1,1,0,1,1],
[0,0,1,0,1,1,0,0,1,0,0,0,1,1,1,0,0,1,0,0,1,0,1,2,0,1,1,0,2],
[0,1,1,0,1,0,1,1,0,0,1,0,0,0,1,1,0,1,0,1,1,1,1,1,2,0,1,2,0],
[0,0,0,0,1,0,1,0,0,0,0,1,0,0,1,0,0,1,1,1,2,0,0,1,0,0,1,1,0],
[0,0,1,1,0,1,1,0,0,1,1,1,1,0,0,1,0,0,1,1,1,0,0,0,1,1,1,0,1],
[0,2,0,1,1,1,1,0,1,0,0,0,0,0,1,1,1,0,1,1,1,1,0,1,0,0,0,1,1],
[0,2,1,1,1,1,1,1,1,1,0,1,1,0,0,0,0,0,1,0,1,1,1,1,1,1,0,1,1],
[0,1,1,1,0,1,0,0,0,1,0,2,0,1,1,1,1,1,0,1,0,1,0,0,1,1,0,1,0],
[0,1,1,1,1,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,0,1,1,0,0,0,0,0],
[1,0,0,0,0,1,0,1,0,1,0,1,0,0,1,0,0,1,0,0,1,0,1,0,0,1,2,1,1]], dtype=DTYPE)
derive_equations(field)
if __name__ == '__main__':
main()
# file setup_so.py
from distutils.core import setup
from Cython.Build import cythonize
import numpy
setup(
name = "test_so",
ext_modules = cythonize('test_so_cy.pyx'),
include_dirs=[numpy.get_include()]
)
# usage: python setup_so.py build_ext --inplace
# import test_so_cy
# test_so_cy.main()
问题是 cython 代码的运行速度比纯 python 版本慢 ~3 倍。 (我正在使用时间模块来测量执行时间,因为对于更大的矩阵没问题)。
cython -a 告诉我
if field[x][j] == block: break
行仍然使用很多 python。所以好像还是不能用fast indexing。 知道我做错了什么吗?
最佳答案
原速度:0.14s
14 倍加速(0.01 秒):field[i][j]
将首先计算 field[i]
,然后尝试计算生成的 python 对象。使用 field[i,j]
符号来大幅提升速度
5 倍加速(0.0018 秒):键入 eq 变量 cdef long eq
12X s5eedup (0.00012s) : 将列表替换为由 np 数组组成的堆栈:
cdef np.ndarray[long, ndim=2] eqs=np.zeros((n*m,3),np.long)
cdef int curr_eqn=0
#append to list code
if field[i,j] == block:
eqs[curr_eqn,0]=i*m+j
eqs[curr_eqn,1]=field[i,j]
eqs[curr_eqn,2]=eq
curr_eqn+=1
continue
总加速:1100 倍
关于python - 使用cython性能下降,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34581856/