org.nd4j.linalg.api.ops.impl.transforms.SpaceToBatch Maven / Gradle / Ivy
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* Copyright (c) 2015-2018 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.api.ops.impl.transforms;
import lombok.val;
import org.nd4j.autodiff.samediff.SDVariable;
import org.nd4j.autodiff.samediff.SameDiff;
import org.nd4j.linalg.api.ops.DynamicCustomOp;
import java.util.Arrays;
import java.util.List;
/**
* N-dimensional space to batch operation. Transforms data from a tensor from M spatial dimensions into batch dimension
* according to the "blocks" specified (a vector of length M). Afterwards the spatial dimensions are optionally padded,
* as specified in "padding", a tensor of dim (M, 2), denoting the padding range.
*
* Example:
* input: [[[[1], [2]], [[3], [4]]]]
* input shape: [1, 2, 2, 1]
* blocks: [2, 2]
* padding: [[0, 0], [0, 0]]
*
* output: [[[[1]]], [[[2]]], [[[3]]], [[[4]]]]
* output shape: [4, 1, 1, 1]
* *
*
* @author Max Pumperla
*/
public class SpaceToBatch extends DynamicCustomOp {
protected int[] blocks;
protected int[][] padding;
public SpaceToBatch() {
}
public SpaceToBatch(SameDiff sameDiff, SDVariable[] args, int[] blocks, int[][] padding, boolean inPlace) {
super(null, sameDiff, args, inPlace);
this.blocks = blocks;
this.padding = padding;
for (val b : blocks)
addIArgument(b);
for (int e = 0; e < padding.length; e++)
addIArgument(padding[e][0], padding[e][1]);
}
@Override
public String opName() {
return "space_to_batch";
}
@Override
public String onnxName() {
return "space_to_batch";
}
@Override
public String tensorflowName() {
return "SpaceToBatchND";
}
@Override
public List doDiff(List i_v) {
// Inverse of space to batch is batch to space with same blocks and crops as padding
SDVariable gradient = sameDiff.setupFunction(i_v.get(0));
return Arrays.asList(sameDiff.batchToSpace(gradient, blocks, padding));
}
}