相关疑难解决方法(0)

I have an array and I would like to produce a smaller array by scanning a 2x2 non-overlappingly windows and getting the maximum. Here is an example:

import numpy as np

np.random.seed(123)
np.set_printoptions(linewidth=1000,precision=3)
arr = np.random.uniform(-1,1,(4,4))
res = np.zeros((2,2))
for i in xrange(res.shape[0]):
    for j in xrange(res.shape[1]):
        ii = i*2
        jj = j*2
        res[i][j] = max(arr[ii][jj],arr[ii+1][jj],arr[ii][jj+1],arr[ii+1][jj+1])

print arr
print res

So a matrix like this:

[[ 0.393 -0.428 -0.546  0.103]
 [ 0.439 -0.154  0.962  0.37 ]
 [-0.038 -0.216 -0.314  0.458] …