Python:absolute value of each element of a matrix inside a loop

Question

In python (I am new working with python), I have a matrix built inside a loop in the following way:

A[:,index_i ,index_j] = B[:,index_i ,index_j] - C[:,index_i ,index_j]

Just after that inside the same loop there are some calculations on A, but before I need to get A with each element positive for those operations, then, writing this will work so each A[k,index_i,index_j]>=0?

A[:,index_i ,index_j]= abs( B[:,index_i ,index_j] - C[:,index_i ,index_j] )

If possible, I want to avoid more loops to have every element positive.

Thank you!

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score 2 · Accepted Answer · answered Jan 15 '21 at 12:38

2

Assuming these are numpy arrays, the below should work quite well:

A[:, i,j] = np.abs(B[:, i, j]- C[:,i, j])

Indeed, you can even skip the i, j loop and simply right:

A = np.abs(B-C)

to get the same outcome in a more pythonic and faster way.

answered Jan 15 '21 at 12:38

supercooler8

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score 1 · Answer 2 · answered Jan 15 '21 at 12:37

1

The builtin abs function accepts a scalar value. You can use numpy's function

import numpy as np
result = np.abs(...)

answered Jan 15 '21 at 12:37

blue_note

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Python:absolute value of each element of a matrix inside a loop

2 Answers2