我尝试优化下面的代码,但我无法弄清楚如何提高计算速度。我试过Cthon,但性能就像在python中一样。
是否可以在不重写C / C ++中的所有内容的情况下提高性能?
感谢您的帮助
import numpy as np
heightSequence = 400
widthSequence = 400
nHeights = 80
DOF = np.zeros((heightSequence, widthSequence), dtype = np.float64)
contrast = np.float64(np.random.rand(heightSequence, widthSequence, nHeights))
initDOF = np.zeros([heightSequence, widthSequence], dtype = np.float64)
initContrast = np.zeros([heightSequence, widthSequence, nHeights], dtype = np.float64)
initHeight = np.float64(np.r_[0:nHeights:1.0])
initPixelContrast = np.array(([0 for ii in range(nHeights)]), dtype = np.float64)
# for each row
for row in range(heightSequence):
# for each col
for col in range(widthSequence):
# initialize variables
height = initHeight # array ndim = 1
c = initPixelContrast # array ndim = 1
# for each height
for indexHeight in range(0, nHeights):
# get contrast profile for current pixel
tempC = contrast[:, :, indexHeight]
c[indexHeight] = tempC[row, col]
# save original contrast
# originalC = c
# originalHeight = height
# remove profile before maximum and after minumum contrast
idxMaxContrast = np.argmax(c)
c = c[idxMaxContrast:]
height = height[idxMaxContrast:]
idxMinContrast = np.argmin(c) + 1
c = c[0:idxMinContrast]
height = height[0:idxMinContrast]
# remove some refraction
if (len(c) <= 1) | (np.max(c) <= 0):
DOF[row, col] = 0
else:
# linear fitting of profile contrast
P = np.polyfit(height, c, 1)
m = P[0]
q = P[1]
# remove some refraction
if m >= 0:
DOF[row, col] = 0
else:
DOF[row, col] = -q / m
print 'row=%i/%i' %(row, heightSequence)
# set range of DOF
DOF[DOF < 0] = 0
DOF[DOF > nHeights] = 0
答案 0 :(得分:4)
通过查看代码,您可以完全摆脱两个外部循环,将代码转换为矢量化形式。但是,np.polyfit
调用必须由其他表达式替换,但线性拟合的系数很容易找到,也是矢量化形式。然后可以将最后一个if-else
转换为np.where
来电。