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* * 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.
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* * SPDX-License-Identifier: Apache-2.0
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*/
package org.nd4j.linalg.api.ops.impl.reduce.custom;
import org.nd4j.autodiff.samediff.SDVariable;
import org.nd4j.autodiff.samediff.SameDiff;
import org.nd4j.common.base.Preconditions;
import org.nd4j.linalg.api.buffer.DataType;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.api.ops.DynamicCustomOp;
import org.nd4j.linalg.api.ops.impl.reduce.bp.SumBp;
import java.util.Collections;
import java.util.List;
public class LogSumExp extends DynamicCustomOp {
protected boolean keepDims;
public LogSumExp(SameDiff sameDiff, SDVariable i_v, boolean keepDims, int[] dimensions) {
super(sameDiff, i_v);
if(dimensions != null) {
addIArgument(dimensions);
this.dimensions = dimensions;
}
addTArgument(keepDims ? 1.0 : 0.0);
this.keepDims = keepDims;
}
public LogSumExp(SameDiff sameDiff, SDVariable i_v, int[] dimensions) {
this(sameDiff, i_v, false, dimensions);
}
public LogSumExp() {}
public LogSumExp(INDArray x, int... dimensions) {
this(x, false, dimensions);
}
public LogSumExp(INDArray x, boolean keepDim, int... dimensions) {
this(x, null, keepDim, dimensions);
}
public LogSumExp(INDArray x, INDArray z, boolean keepDim, int... dimensions) {
super(null, x,z, Collections.singletonList(keepDim ? 1.0 : 0.0), dimensions);
}
@Override
public String opName() {
return "reduce_logsumexp";
}
@Override
public List calculateOutputDataTypes(List dataTypes){
Preconditions.checkState(dataTypes != null && (dataTypes.size() == 1 || dataTypes.size() == 2),
"Expected 1 or 2 input datatypes for %s, got %s", getClass(), dataTypes);
return Collections.singletonList(dataTypes.get(0));
}
@Override
public List doDiff(List f1) {
//z = log(sum_i exp(x_i)) = log(s)
//dL/dx = dL/dz * dz/ds * ds/dx
//dz/ds = 1/s
SDVariable exp = sameDiff.math.exp(arg());
SDVariable sumExp = null;
if(dimensions == null) {
if(args().length < 2) {
dimensions = new int[]{Integer.MAX_VALUE};
sumExp = exp.sum(dimensions);
} else {
sumExp = sameDiff.math().sum(exp,arg(1));
}
}
SDVariable gradProd = f1.get(0).div(sumExp);
if(dimensions == null && args().length > 1) {
SDVariable dSumExpdx = new SumBp(sameDiff, arg(), gradProd, keepDims, arg(1)).outputVariable().mul(exp);
return Collections.singletonList(dSumExpdx);
} else {
SDVariable dSumExpdx = new SumBp(sameDiff, arg(), gradProd, keepDims, dimensions).outputVariable().mul(exp);
return Collections.singletonList(dSumExpdx);
}
}
@Override
public String onnxName() {
return "ReduceLogSumExp";
}
}