tf.compat.v1.nn.depthwise_conv2d

Depthwise 2-D convolution.

Given a 4D input tensor ('NHWC' or 'NCHW' data formats) and a filter tensor of shape [filter_height, filter_width, in_channels, channel_multiplier] containing in_channels convolutional filters of depth 1, depthwise_conv2d applies a different filter to each input channel (expanding from 1 channel to channel_multiplier channels for each), then concatenates the results together. The output has in_channels * channel_multiplier channels.

In detail, with the default NHWC format,

output[b, i, j, k * channel_multiplier + q] = sum_{di, dj}
     filter[di, dj, k, q] * input[b, strides[1] * i + rate[0] * di,
                                     strides[2] * j + rate[1] * dj, k]

Must have strides[0] = strides[3] = 1. For the most common case of the same horizontal and vertical strides, strides = [1, stride, stride, 1]. If any value in rate is greater than 1, we perform atrous depthwise convolution, in which case all values in the strides tensor must be equal to 1.

Usage Example:

x = np.array([
    [1., 2.],
    [3., 4.],
    [5., 6.]
], dtype=np.float32).reshape((1, 3, 2, 1))
kernel = np.array([
    [1., 2.],
    [3., 4]
], dtype=np.float32).reshape((2, 1, 1, 2))