InputVertex.java

/*-
 *
 *  * Copyright 2016 Skymind,Inc.
 *  *
 *  *    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.
 *
 */

package org.deeplearning4j.nn.graph.vertex.impl;

import org.deeplearning4j.berkeley.Pair;
import org.deeplearning4j.nn.api.Layer;
import org.deeplearning4j.nn.api.MaskState;
import org.deeplearning4j.nn.gradient.Gradient;
import org.deeplearning4j.nn.graph.ComputationGraph;
import org.deeplearning4j.nn.graph.vertex.BaseGraphVertex;
import org.deeplearning4j.nn.graph.vertex.VertexIndices;
import org.nd4j.linalg.api.ndarray.INDArray;

/** An InputVertex simply defines the location (and connection structure) of inputs to the ComputationGraph.
 * It does not define forward or backward methods.
 */
public class InputVertex extends BaseGraphVertex {


    public InputVertex(ComputationGraph graph, String name, int vertexIndex, VertexIndices[] outputVertices) {
        super(graph, name, vertexIndex, null, outputVertices);
    }

    @Override
    public boolean hasLayer() {
        return false;
    }

    @Override
    public boolean isOutputVertex() {
        return false;
    }

    @Override
    public boolean isInputVertex() {
        return true;
    }

    @Override
    public Layer getLayer() {
        return null;
    }

    @Override
    public INDArray doForward(boolean training) {
        throw new UnsupportedOperationException("Cannot do forward pass for InputVertex");
    }

    @Override
    public Pair<Gradient, INDArray[]> doBackward(boolean tbptt) {
        throw new UnsupportedOperationException("Cannot do backward pass for InputVertex");
    }

    @Override
    public void setBackpropGradientsViewArray(INDArray backpropGradientsViewArray) {
        if (backpropGradientsViewArray != null)
            throw new RuntimeException("Vertex does not have gradients; gradients view array cannot be set here");
    }

    @Override
    public Pair<INDArray, MaskState> feedForwardMaskArrays(INDArray[] maskArrays, MaskState currentMaskState,
                    int minibatchSize) {
        //No op
        if (maskArrays == null || maskArrays.length == 0) {
            return null;
        }

        return new Pair<>(maskArrays[0], currentMaskState);
    }

    @Override
    public String toString() {
        return "InputVertex(id=" + vertexIndex + ",name=\"" + vertexName + "\")";
    }
}