python numpy 手写maxpooling，超简洁写法

简洁易懂

def max_pooling(image, pooling_size, stride):
    c,h,w = image.shape()
    p_h,p_w = pooling_size.shape()

    out_h = (h-p_h)//stride+1
    out_w = (w-p_w)//stride+1
    out = np.zeros((c,out_h, out_w))

    for i in range(c):
        for x in range(out_h):
            for y in range(out_w):
                out[i][x][y] = np.max(image[i][x*stride:(x+1)*stride][y*stride:(y+1)*stride])
    return out