你先导入numpy.cos，然后再导入math.cos.后者掩盖了前者，并且不知道如何处理 NumPy 数组.因此出现错误.

You first import numpy.cos, and then import math.cos. The latter shadows the former, and doesn't know how to handle NumPy arrays. Hence the error.

要修复，请尝试:

import numpy

def CosineMap(a,x):
    return a*numpy.cos(x/(2.*pi))

这类问题是避免 from X import * 样式导入的一个很好的理由.

Problems of this sort are a good reason to avoid from X import *-style imports.

对于 TentMap，这里是一种正确矢量化的方法:

As to TentMap, here is one way to vectorize it correctly:

def TentMap(a,x):
    return 2.*a*numpy.minimum(x, 1.-x)