org.nd4j.linalg.dataset.api.preprocessor.PermuteDataSetPreProcessor Maven / Gradle / Ivy
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* Copyright (c) 2015-2019 Skymind, Inc.
*
* 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.
*
* 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.dataset.api.preprocessor;
import org.nd4j.base.Preconditions;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.dataset.api.DataSet;
import org.nd4j.linalg.dataset.api.DataSetPreProcessor;
/**
* The PermuteDataSetPreProcessor will rearrange the dimensions.
* There are two pre-defined permutation types:
* - from NCHW to NHWC
* - from NHWC to NCHW
*
* Or, pass the new order to the ctor. For example PermuteDataSetPreProcessor(1, 2, 0) will rearrange the middle dimension first, the last one in the middle and the first one last.
*
* @author Alexandre Boulanger
*/
public class PermuteDataSetPreProcessor implements DataSetPreProcessor {
private final PermutationTypes permutationType;
private final int[] rearrange;
public enum PermutationTypes { NCHWtoNHWC, NHWCtoNCHW, Custom }
public PermuteDataSetPreProcessor(PermutationTypes permutationType) {
Preconditions.checkArgument(permutationType != PermutationTypes.Custom, "Use the ctor PermuteDataSetPreProcessor(int... rearrange) for custom permutations.");
this.permutationType = permutationType;
rearrange = null;
}
/**
* @param rearrange The new order. For example PermuteDataSetPreProcessor(1, 2, 0) will rearrange the middle dimension first, the last one in the middle and the first one last.
*/
public PermuteDataSetPreProcessor(int... rearrange) {
this.permutationType = PermutationTypes.Custom;
this.rearrange = rearrange;
}
@Override
public void preProcess(DataSet dataSet) {
Preconditions.checkNotNull(dataSet, "Encountered null dataSet");
if(dataSet.isEmpty()) {
return;
}
INDArray input = dataSet.getFeatures();
INDArray output;
switch (permutationType) {
case NCHWtoNHWC:
output = input.permute(0, 2, 3, 1);
break;
case NHWCtoNCHW:
output = input.permute(0, 3, 1, 2);
break;
case Custom:
output = input.permute(rearrange);
break;
default:
output = input;
break;
}
dataSet.setFeatures(output);
}
}