为每个python numpy用不同的值填充矩阵对角线 [英] Fill matrix diagonal with different values for each python numpy

问题描述

我看到了一个函数numpy.fill_diagonal，该函数为对角线元素分配相同的值.但是我想为每个对角线元素分配不同的随机值.我该如何在python中做到这一点?可能正在使用scipy或其他库?

I saw a function numpy.fill_diagonal which assigns same value for diagonal elements. But I want to assign different random values for each diagonal elements. How can I do it in python ? May be using scipy or other libraries ?

推荐答案

您可以使用 np.diag_indices 来获取那些索引，然后使用这些索引简单地索引到数组中并分配值.

You can use np.diag_indices to get those indices and then simply index into the array with those and assign values.

这里是一个示例运行来说明它-

Here's a sample run to illustrate it -

In [86]: arr          # Input array
Out[86]: 
array([[13, 69, 35, 98, 16],
       [93, 42, 72, 51, 65],
       [51, 33, 96, 43, 53],
       [15, 26, 16, 17, 52],
       [31, 54, 29, 95, 80]])

# Get row, col indices
In [87]: row,col = np.diag_indices(arr.shape[0])

# Assign values, let's say from an array to illustrate
In [88]: arr[row,col] = np.array([100,200,300,400,500])

In [89]: arr
Out[89]: 
array([[100,  69,  35,  98,  16],
       [ 93, 200,  72,  51,  65],
       [ 51,  33, 300,  43,  53],
       [ 15,  26,  16, 400,  52],
       [ 31,  54,  29,  95, 500]])

您还可以使用 np.diag_indices_from 可能会更像偶像，就像这样-

You can also use np.diag_indices_from and probably would be more idomatic, like so -

row, col = np.diag_indices_from(arr)

注意::尝试过的功能可以正常工作.在先前的问答中也对此进行了讨论- Numpy修改ndarray对角线.

Note : The tried function would work just fine. This is discussed in a previous Q&A - Numpy modify ndarray diagonal too.

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