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2026-07-13 12:47:05 +08:00

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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.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
//
// @author Yurii Shyrma (iuriish@yahoo.com), created on 18.06.2018
//
#include <system/op_boilerplate.h>
#if NOT_EXCLUDED(OP_softmax_cross_entropy_loss_with_logits)
#include <ops/declarable/CustomOperations.h>
namespace sd {
namespace ops {
//////////////////////////////////////////////////////////////////////////
CUSTOM_OP_IMPL(softmax_cross_entropy_loss_with_logits, 2, 1, false, 0, 0) {
auto logits = INPUT_VARIABLE(0);
auto labels = INPUT_VARIABLE(1);
auto output = OUTPUT_VARIABLE(0);
const int classesDim = block.getIArguments()->size() > 0 ? INT_ARG(0) : logits->rankOf() - 1;
// input validation
REQUIRE_TRUE(labels->isSameShape(logits), 0,
"SOFTMAX_CROSS_ENTROPY_LOSS_WITH_LOGITS OP: labels and logits arrays must have the same shapes, but got "
"%s and %s correspondingly !",
ShapeUtils::shapeAsString(labels).c_str(), ShapeUtils::shapeAsString(logits).c_str());
REQUIRE_TRUE(classesDim < logits->rankOf(), 0,
"SOFTMAX_CROSS_ENTROPY_LOSS_WITH_LOGITS OP: class dimension must be smaller than rank of logits, but "
"got %i and %i correspondingly !",
classesDim, logits->rankOf());
std::vector<LongType> dimension = {classesDim};
// Compute softmax log
NDArray* maxAlongDim_ptr = logits->reduceAlongDimension(reduce::Max, &dimension, true);
NDArray maxAlongDim = *maxAlongDim_ptr;
delete maxAlongDim_ptr;
NDArray* shiftedLogits_ptr = (*logits) - maxAlongDim;
NDArray* logExp_ptr = shiftedLogits_ptr->transform(transform::Exp);
delete shiftedLogits_ptr;
NDArray logExp = *logExp_ptr;
delete logExp_ptr;
NDArray* sumLogExp_ptr = logExp.reduceAlongDimension(reduce::Sum, &dimension, true);
NDArray sumLogExp = *sumLogExp_ptr;
delete sumLogExp_ptr;
NDArray* softmaxRatio_ptr = logExp / sumLogExp;
NDArray* logSoftMax_ptr = softmaxRatio_ptr->transform(transform::Log);
delete softmaxRatio_ptr;
NDArray logSoftMax = *logSoftMax_ptr;
delete logSoftMax_ptr;
// Compute cross entropy: -labels * log(softmax)
NDArray negLabels = -(*labels); // unary negation returns value
NDArray* product_ptr = negLabels * logSoftMax;
product_ptr->reduceAlongDimension(reduce::Sum, output, &dimension);
delete product_ptr;
return Status::OK;
}
//////////////////////////////////////////////////////////////////////////
DECLARE_TYPES(softmax_cross_entropy_loss_with_logits) {
getOpDescriptor()->setAllowedInputTypes(ANY)->setAllowedOutputTypes({ALL_FLOATS});
}
//////////////////////////////////////////////////////////////////////////
DECLARE_SHAPE_FN(softmax_cross_entropy_loss_with_logits) {
auto logitsShapeInfo = inputShape->at(0);
auto labelsShapeInfo = inputShape->at(1);
const int classesDim = block.getIArguments()->size() > 0 ? INT_ARG(0) : -1;
std::vector<LongType> dimensions = {classesDim};
// labels and logits must have the same shapes
REQUIRE_TRUE(shape::shapeEquals(logitsShapeInfo, labelsShapeInfo), 0,
"SOFTMAX_CROSS_ENTROPY_LOSS_WITH_LOGITS OP: labels and logits arrays must have the same shapes, but got "
"%s and %s correspondingly!",
ShapeUtils::shapeAsString(labelsShapeInfo).c_str(), ShapeUtils::shapeAsString(logitsShapeInfo).c_str());
auto outType = DataTypeUtils::pickFloatingType(ArrayOptions::dataType(logitsShapeInfo));
auto reducedShapeInfo = ShapeUtils::evalReduceShapeInfo(shape::order(labelsShapeInfo), &dimensions, labelsShapeInfo,
outType, false, false, block.getWorkspace());
return SHAPELIST(reducedShapeInfo);
}
//////////////////////////////////////////////////////////////////////////
CUSTOM_OP_IMPL(softmax_cross_entropy_loss_with_logits_grad, 2, 2, false, 0, 0) {
auto logits = INPUT_VARIABLE(0);
auto labels = INPUT_VARIABLE(1);
auto output = OUTPUT_VARIABLE(0);
auto dLdp = OUTPUT_VARIABLE(0); // dL/dlogits
auto dLdl = OUTPUT_VARIABLE(1); // dL/dlabels
const int classesDim = block.getIArguments()->size() > 0 ? INT_ARG(0) : logits->rankOf()-1;
// input validation
REQUIRE_TRUE(labels->isSameShape(logits), 0,
"SOFTMAX_CROSS_ENTROPY_LOSS_WITH_LOGITS_GRAD OP: labels and logits arrays must have the same shapes, "
"but got %s and %s correspondingly !",
ShapeUtils::shapeAsString(labels).c_str(), ShapeUtils::shapeAsString(logits).c_str());
REQUIRE_TRUE(classesDim < logits->rankOf(), 0,
"SOFTMAX_CROSS_ENTROPY_LOSS_WITH_LOGITS_GRAD OP: class dimension must be smaller than rank of logits, "
"but got %i and %i correspondingly !",
classesDim, logits->rankOf());
std::vector<LongType> dimension = {classesDim};
// Compute softmax
NDArray* maxAlongDim_ptr = logits->reduceAlongDimension(reduce::Max, &dimension, true);
NDArray maxAlongDim = *maxAlongDim_ptr;
delete maxAlongDim_ptr;
NDArray* shiftedLogits_ptr = (*logits) - maxAlongDim;
NDArray* softmax_ptr = shiftedLogits_ptr->transform(transform::Exp);
delete shiftedLogits_ptr;
NDArray softmax = *softmax_ptr;
delete softmax_ptr;
NDArray* sumSoftmax_ptr = softmax.reduceAlongDimension(reduce::Sum, &dimension, true);
NDArray sumSoftmax = *sumSoftmax_ptr;
delete sumSoftmax_ptr;
softmax /= sumSoftmax;
// dEdp = softmax * sum_i(labels_i) - labels
// note the eps is to account for exact 0s in the log calculation being nan
NDArray* labelsPlusEps_ptr = (*labels) + 1e-6;
NDArray labelsPlusEps = *labelsPlusEps_ptr;
delete labelsPlusEps_ptr;
NDArray* labelSum_ptr = labelsPlusEps.reduceAlongDimension(reduce::Sum, &dimension, true);
NDArray labelSum = *labelSum_ptr;
delete labelSum_ptr;
NDArray* softmaxTimesLabelSum_ptr = softmax * labelSum;
NDArray* dLdpTemp_ptr = (*softmaxTimesLabelSum_ptr) - labelsPlusEps;
delete softmaxTimesLabelSum_ptr;
dLdp->assign(dLdpTemp_ptr);
delete dLdpTemp_ptr;
// dEdl = -log(softmax)
softmax.applyTransform(transform::Log, dLdl);
dLdl->applyTransform(transform::Neg, dLdl);
return Status::OK;
}
//////////////////////////////////////////////////////////////////////////
DECLARE_TYPES(softmax_cross_entropy_loss_with_logits_grad) {
getOpDescriptor()->setAllowedInputTypes(ANY)->setAllowedOutputTypes({ALL_FLOATS});
}
//////////////////////////////////////////////////////////////////////////
DECLARE_SHAPE_FN(softmax_cross_entropy_loss_with_logits_grad) {
auto logitsShapeInfo = inputShape->at(0);
auto labelsShapeInfo = inputShape->at(1);
// labels and logits must have the same shapes
REQUIRE_TRUE(shape::shapeEquals(logitsShapeInfo, labelsShapeInfo), 0,
"SOFTMAX_CROSS_ENTROPY_LOSS_WITH_LOGITS_GRAD OP: labels and logits arrays must have the same shapes, "
"but got %s and %s correspondingly!",
ShapeUtils::shapeAsString(labelsShapeInfo).c_str(), ShapeUtils::shapeAsString(logitsShapeInfo).c_str());
DataType outType = DataTypeUtils::pickFloatingType(ArrayOptions::dataType(logitsShapeInfo));
auto dLdpShapeInfo = ConstantShapeHelper::getInstance().bufferForShapeInfo(outType, shape::order(logitsShapeInfo),
shape::rank(logitsShapeInfo),
shape::shapeOf(logitsShapeInfo))->primary();
auto dLdlShapeInfo = ConstantShapeHelper::getInstance().bufferForShapeInfo(outType, shape::order(labelsShapeInfo),
shape::rank(labelsShapeInfo),
shape::shapeOf(labelsShapeInfo))->primary();
return SHAPELIST(dLdpShapeInfo, dLdlShapeInfo);
}
} // namespace ops
} // namespace sd
#endif