python正弦和余弦精度 [英] python sine and cosine precision

问题描述

如何提高python正弦和余弦精度?例如，我想使用跟随代码(对于随机复数x只需计算y = cos(acos(x))):

How to improve python sine and cosine precision? For example I want to use follow code (just calculate y = cos(acos(x)) for a random complex vector x):

import numpy as np
N = 100000
x = np.zeros(N)+1j*np.zeros(N)
for k in range(0,N):
    x[k] = np.random.normal(0,500)+1j*np.random.normal(0,500)    
y = np.cos(np.arccos(x))

m= np.max(np.abs(x))

print np.max(np.abs(x-y)/m)

y 必须等于 x .但是我的区别大约是 1E-9 .我觉得太大了.例如，对于相同的测试，matlab返回的小于1E-15 .有什么方法可以提高python的精度吗?谢谢！

y must be equal x. But my difference is approx 1E-9. I think is too big. For example matlab returns less than 1E-15 for the same test. There is some way to improve python precision? Thanks!

推荐答案

重新安装python后，问题消失了.感谢您的评论

Problem is disappear after python reinstall. Thanks for comments

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