numpy数值计算实例

∑ i = − 50 50 ∑ j = − 50 50 ∑ k = − 50 50 1 i 2 + j 2 + k 2 − 0.25 sum_{i=-50}^{50}sum_{j=-50}^{50}sum_{k=-50}^{50}frac{1}{i^2+j^2+k^2-0.25} i=−50∑50​j=−50∑50​k=−50∑50​i2+j2+k2−0.251​
代码：

import numpy as np
k = 50
N = 2*k+1
n1 = np.arange(-k, k+1, 1)
n1 = np.tile(n1[:, np.newaxis, np.newaxis], (1,N,N))
n2 = np.arange(-k, k+1, 1)
n2 = np.tile(n2[np.newaxis, :, np.newaxis], (N,1,N))
n3 = np.arange(-k, k+1, 1)
n3 = np.tile(n3[np.newaxis, np.newaxis, :], (N,N,1))
rst = 1/(n1**2 + n2**2 + n3**2 - 0.25)
print(rst.sum())