/*****************************************************************************

Copyright 2018 The TensorFlow.NET Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");

you may not use this file except in compliance with the License.

You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software

distributed under the License is distributed on an "AS IS" BASIS,

WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

See the License for the specific language governing permissions and

limitations under the License.

******************************************************************************/

using System.Linq;

namespace Tensorflow.Keras.Layers

{

/// <summary>

/// A `Node` describes the connectivity between two layers.

/// </summary>

public class Node

{

public InputLayer outbound_layer;

public Layer[] inbound_layers;

public int[] node_indices;

public int[] tensor_indices;

public Tensor[] input_tensors;

public Tensor[] output_tensors;

public int[][] input_shapes;

public int[][] output_shapes;

/// <summary>

///

/// </summary>

/// <param name="outbound_layer">

/// the layer that takes

/// `input_tensors` and turns them into `output_tensors`

/// (the node gets created when the `call`

/// method of the layer was called).

/// </param>

/// <param name="inbound_layers">

/// a list of layers, the same length as `input_tensors`,

/// the layers from where `input_tensors` originate.

/// </param>

/// <param name="node_indices">

/// a list of integers, the same length as `inbound_layers`.

/// `node_indices[i]` is the origin node of `input_tensors[i]`

/// (necessary since each inbound layer might have several nodes,

/// e.g. if the layer is being shared with a different data stream).

/// </param>

/// <param name="tensor_indices"></param>

/// <param name="input_tensors">list of input tensors.</param>

/// <param name="output_tensors">list of output tensors.</param>

public Node(InputLayer outbound_layer,

Layer[] inbound_layers,

int[] node_indices,

int[] tensor_indices,

Tensor[] input_tensors,

Tensor[] output_tensors)

{

this.outbound_layer = outbound_layer;

this.inbound_layers = inbound_layers;

this.node_indices = node_indices;

this.tensor_indices = tensor_indices;

this.input_tensors = input_tensors;

this.output_tensors = output_tensors;

input_shapes = input_tensors.Select(x => x._shape_tuple()).ToArray();

output_shapes = output_tensors.Select(x => x._shape_tuple()).ToArray();

// Add nodes to all layers involved.

foreach (var layer in inbound_layers)

{

if (layer != null)

layer.outbound_nodes.Add(this);

}

outbound_layer.inbound_nodes.Add(this);

}

}

}