#设置成“valid”?

Question

老师，pooling为啥一定要都设为same,不能有些设same,有些设valid，这个可以理解，那么，全都设成valid怎么样？？

Answer 1

正十七 2020-03-24 20:02:43

这是我们resnet block的代码：

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def residual_block(x, output_channel):     """residual connection implementation"""     input_channel = x.get_shape().as_list()[-1]     if input_channel * 2 == output_channel:         increase_dim = True         strides = (2, 2)     elif input_channel == output_channel:         increase_dim = False         strides = (1, 1)     else:         raise Exception("input channel can't match output channel")     conv1 = tf.layers.conv2d(x,                              output_channel,                              (3,3),                              strides = strides,                              padding = 'same',                              activation = tf.nn.relu,                              name = 'conv1')     conv2 = tf.layers.conv2d(conv1,                              output_channel,                              (3, 3),                              strides = (1, 1),                              padding = 'same',                              activation = tf.nn.relu,                              name = 'conv2')     if increase_dim:                # [None, image_width, image_height, channel] -> [,,,channel*2]         pooled_x = tf.layers.average_pooling2d(x,                                                (2, 2),                                                (2, 2),                                                padding = 'valid')         padded_x = tf.pad(pooled_x,                           [[0,0],                            [0,0],                            [0,0],                            [input_channel // 2, input_channel // 2]])     else:         padded_x = x     output_x = conv2 + padded_x     return output_x

在做pooling的时候，我们用了valid。

其实不管是same还是valid，因为做pooling总是要变小的。所以变小之后你得保证做了tf.pad后能跟conv2的shape是一样的。保证了这一点后，用valid还是same都可以的。