python3中np. divide(x，y)和xy有什么区别'

我最近发现代码中有一个bug，我可以用x / y替换np.divide(x, y)来修复它.

我的印象是np. divide(x，y)等同于x/y(numpy文档中也有这么多).

这是麻木中的一个错误，还是意料之中的行为？

正如我所说的，我眼前的问题已经解决了，所以我不太担心找到解决办法，我更好奇地想知道发生了什么.

import numpy as np


x1 = np.array([[281], [15831], [30280], [975], [313], [739], [252], [10364], [21480], [1447], [315], [772], [95], [2710], [7408], [215], [111], [158], [0], [88], [21], [661], [0], [0], [0], [5], [4], [0], [12], [0], [0], [50], [28], [0], [0], [272]])
x2 = np.array([[499], [6315], [33800], [580], [208], [464], [384], [3127], [19596], [2319], [218], [1740], [217], [411], [4250], [223], [406], [267], [2], [0], [16], [0], [0], [0], [0], [8], [3], [0], [18], [0], [1], [0], [41], [0], [0], [0]])
x3 = np.array([[507], [6180], [34005], [555], [200], [451], [390], [3024], [19492], [2425], [211], [1848], [223], [396], [4097], [224], [406], [282], [2], [0], [16], [0], [0], [0], [0], [8], [3], [0], [19], [0], [2], [0], [45], [0], [0], [0]])
x4 = np.array([[507], [6178], [34017], [554], [200], [451], [391], [3022], [19486], [2439], [210], [1865], [223], [396], [4089], [224], [406], [284], [2], [0], [16], [0], [0], [0], [0], [8], [3], [0], [19], [0], [2], [0], [46], [0], [0], [0]])

not_zero = (x1 + x2) != 0
x = np.divide(2*(x1 - x2)**2, x1 + x2, where=not_zero)
r = (2*(x1[not_zero] - x2[not_zero])**2) / (x1[not_zero] + x2[not_zero])
print("n1 =",x.max(),"\tt1 =", r.max())

not_zero = (x2 + x3) != 0
x = np.divide(2*(x2 - x3)**2, x2 + x3, where=not_zero)
r = (2*(x2[not_zero] - x3[not_zero])**2) / (x2[not_zero] + x3[not_zero])
print("n2 =",x.max(),"\tt2 =", r.max())

not_zero = (x3 + x4) != 0
x = np.divide(2*(x3 - x4)**2, x3 + x4, where=not_zero)
r = (2*(x3[not_zero] - x4[not_zero])**2) / (x3[not_zero] + x4[not_zero])
print("n3 =",x.max(),"\tt3 =", r.max())

Output:个

n1 = 8177.933351395286  t1 = 8177.933351395286
n2 = 873842.0           t2 = 6.501672240802676
n3 = 1322.0             t3 = 0.15566927013196877

Python版本:3.7.6 Numpy版本:1.17.0