/*
 *  ******************************************************************************
 *  *
 *  *
 *  * This program and the accompanying materials are made available under the
 *  * terms of the Apache License, Version 2.0 which is available at
 *  * https://www.apache.org/licenses/LICENSE-2.0.
 *  *
 *  *  See the NOTICE file distributed with this work for additional
 *  *  information regarding copyright ownership.
 *  * 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.
 *  *
 *  * SPDX-License-Identifier: Apache-2.0
 *  *****************************************************************************
 */

package org.nd4j.linalg.api.ops.impl.layers.recurrent.weights;

import lombok.Builder;
import lombok.Data;
import lombok.EqualsAndHashCode;
import org.nd4j.autodiff.samediff.SDVariable;
import org.nd4j.linalg.api.ndarray.INDArray;

@EqualsAndHashCode(callSuper = true)
@Data
@Builder
public class LSTMWeights extends RNNWeights {

    /**
     * Input to hidden weights and hidden to hidden weights, with a shape of [inSize + numUnits, 4*numUnits].
     *
     * Input to hidden and hidden to hidden are concatenated in dimension 0,
     * so the input to hidden weights are [:inSize, :] and the hidden to hidden weights are [inSize:, :].
     */
    private SDVariable weights;
    private INDArray iWeights;

    /**
     * Cell peephole (t-1) connections to input modulation gate, with a shape of [numUnits].
     */
    private SDVariable inputPeepholeWeights;
    private INDArray iInputPeepholeWeights;

    /**
     * Cell peephole (t-1) connections to forget gate, with a shape of [numUnits].
     */
    private SDVariable forgetPeepholeWeights;
    private INDArray iForgetPeepholeWeights;

    /**
     * Cell peephole (t) connections to output gate, with a shape of [numUnits].
     */
    private SDVariable outputPeepholeWeights;
    private INDArray iOutputPeepholeWeights;

    /**
     * Input to hidden and hidden to hidden biases, with shape [1, 4*numUnits].
     */
    private SDVariable bias;
    private INDArray iBias;

    @Override
    public SDVariable[] args() {
        return filterNonNull(weights, inputPeepholeWeights, forgetPeepholeWeights, outputPeepholeWeights, bias);
    }

    @Override
    public INDArray[] arrayArgs() {
        return filterNonNull(iWeights, iInputPeepholeWeights, iForgetPeepholeWeights, iOutputPeepholeWeights, iBias);
    }
}
