Add Conv1DTranspose, Conv2DTranspose, Conv3DTranspose layers

[zaleslaw]

Currently, the support for Conv2DTranspose and Conv3DTranspose, Conv1DTranspose are missed, and it would be great to add support for these layers. The desired PR addressing this issue should include:

• Implementation of layer class named as Conv2DTranspose (you can take inspiration from the implementation of Conv2D as reference)
• Implementation of layer class named as Conv3DTranspose (you can take inspiration from the implementation of Conv3D as reference)
• Implementation of layer class named as Conv1DTranspose
• Common hierarchy of all ConvTranspose layers with abstract class with the common functionality
• Documentation of layer and all non-private methods
• JUnit tests in api module
• Support for export of layer to JSON (see ModelSaver.kt)
• Support for import of layer from JSON (see ModelLoader.kt)

This operation is sometimes called "deconvolution" after Deconvolutional Networks

De-convolution could be implemented internally via tf.nn.conv2dBackpropInput or tf.nn.conv3dBackpropInput, also you need to implement analogue of convOutputLength function.

Also, if needed, you can take a look at Keras documentation for Conv2DTranspose, and Conv3DTranspose.

NOTE: for the moment, there is no need to add support for "data format" (i.e., channels last vs. channels first) in your PR; you can assume the channels are always in the last dimension.

P.S. If you want to take this ticket, please leave the comment below
P.P.S Read the Contributing Guidelines.

[avan1235]

I would like to take this issue to get to know the ConvTranspose layers if it possible 😊

@zaleslaw I suppose we can add also the Conv1DTranspose layer?

[zaleslaw]

I'm not sure about the Conv1DTranspose layer, it's not added to the Keras, please write here, if you have any ideas/or found some useful articles about its implementations

[avan1235]

I found it here and then think about adding also to KotlinDL. Isn't it the layer that we are thinking about?

[mkaze]

@zaleslaw Actually, it exists in TF Keras: https://www.tensorflow.org/api_docs/python/tf/keras/layers/Conv1DTranspose
But it's not listed in Keras doc website. And, for the moment, Keras API actually just redirects to TF Keras; so it makes sense to have it.

[zaleslaw]

Great @mkaze @avan1235 I've updated an issue

[zaleslaw]

@avan1235 partially implemented this, but now have no time to finish this PR. It could be a good starting point for future implementations.