仅沿一个轴进行卷积 [英] Convolution along one axis only

问题描述

我有两个具有相同第一轴尺寸的二维数组.在python中，我只想沿第二个轴对两个矩阵进行卷积.我想在不计算沿第一轴的卷积的情况下获得C.

I have two 2-D arrays with the same first axis dimensions. In python, I would like to convolve the two matrices along the second axis only. I would like to get C below without computing the convolution along the first axis as well.

import numpy as np
import scipy.signal as sg

M, N, P = 4, 10, 20
A = np.random.randn(M, N)
B = np.random.randn(M, P)

C = sg.convolve(A, B, 'full')[(2*M-1)/2]

有没有快速的方法?

推荐答案

您可以使用np.apply_along_axis沿所需的轴应用np.convolve.这是将Boxcar滤镜应用于2d数组的示例:

You can use np.apply_along_axis to apply np.convolve along the desired axis. Here is an example of applying a boxcar filter to a 2d array:

import numpy as np

a = np.arange(10)
a = np.vstack((a,a)).T

filt = np.ones(3)

np.apply_along_axis(lambda m: np.convolve(m, filt, mode='full'), axis=0, arr=a)

这是一种概括许多没有axis参数的函数的简便方法.

This is an easy way to generalize many functions that don't have an axis argument.

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