Files
alibaba--mnn/tools/train/source/grad/OpGrad.cpp
T
2026-07-13 13:33:03 +08:00

216 lines
7.8 KiB
C++

//
// OpGrad.cpp
// MNN
//
// Created by MNN on 2019/05/05.
// Copyright © 2018, Alibaba Group Holding Limited
//
#include <mutex>
#include "OpGrad.hpp"
using namespace std;
using namespace MNN::Express;
//#define MNN_TRAIN_DEBUG
namespace MNN {
extern void registerGradOps();
static std::map<int, OpGrad*>& getConverter() {
static std::map<int, OpGrad*> gConverterMap;
return gConverterMap;
}
OpGrad* OpGrad::get(int type) {
auto& converterMap = getConverter();
auto iter = converterMap.find(type);
if (iter != converterMap.end()) {
return iter->second;
}
return nullptr;
}
void OpGrad::insert(int type, OpGrad* converter) {
auto& converterMap = getConverter();
converterMap.insert(std::make_pair(type, converter));
}
std::vector<Express::VARP> OpGrad::gradLinear(Express::VARP loss, const std::vector<Express::VARP>& parameters, const std::vector<Express::VARP>& outputDiff, const std::vector<std::string> blockExpr) {
std::map<EXPRP, std::vector<VARP>> backwardMap;
auto outputSize = loss->expr().first->outputSize();
if (outputSize != outputDiff.size()) {
MNN_ERROR("The expr output %d, but diff size is %d\n", outputSize, (int)outputDiff.size());
return {};
}
backwardMap[loss->expr().first] = outputDiff;
std::set<VARP> parameterSet;
for (auto p : parameters) {
parameterSet.insert(p);
}
auto res = gradCommon({loss}, parameterSet, backwardMap, blockExpr);
std::vector<VARP> linearRes(parameters.size(), nullptr);
for (int i=0; i<parameters.size(); ++i) {
auto iter = res.find(parameters[i]);
if (iter != res.end()) {
linearRes[i] = iter->second;
}
}
return linearRes;
}
std::map<Express::VARP, Express::VARP> OpGrad::grad(VARP loss, const std::set<Express::VARP>& parameters, const std::vector<std::string> blockName) {
std::map<EXPRP, std::vector<VARP>> backwardMap;
{
auto shape = loss->getInfo();
MNN_ASSERT(shape->size == 1);
auto init = _Const(1.0f, shape->dim, shape->order);
backwardMap[loss->expr().first] = std::vector<VARP>{init};
}
return gradCommon({loss}, parameters, backwardMap, blockName);
}
Express::VARP OpGrad::divideAvoidZero(MNN::Express::VARP y, MNN::Express::VARP x) {
auto p = MNN::Express::_Abs(x);
auto sx = MNN::Express::_Sign(x);
p = MNN::Express::_Maximum(p, MNN::Express::_Scalar<float>(0.000001f));
return MNN::Express::_Divide(y, p) * sx;
}
static std::once_flag gInit;
void OpGrad::init() {
std::call_once(gInit, []() {
registerGradOps();
});
}
std::pair<std::vector<Express::VARP>, std::vector<Express::VARP>> OpGrad::gradCommon(std::vector<Express::VARP> outputs, std::vector<Express::VARP> outputDiff, std::vector<Express::VARP> parameters) {
if (outputs.size() != outputDiff.size()) {
MNN_ERROR("outputDiff size %d not equal output size %d\n", (int)outputs.size(), (int)outputDiff.size());
return {};
}
std::map<EXPRP, std::vector<VARP>> backwardMap;
for (int i=0; i<outputs.size(); ++i) {
auto expr = outputs[i]->expr();
if (backwardMap.find(expr.first) == backwardMap.end()) {
std::vector<Express::VARP> res(expr.first->outputSize(), nullptr);
backwardMap.insert(std::make_pair(expr.first, res));
}
auto iter = backwardMap.find(expr.first);
if (nullptr == iter->second[expr.second]) {
iter->second[expr.second] = outputDiff[i];
} else {
iter->second[expr.second] = iter->second[expr.second] + outputDiff[i];
}
}
std::set<Express::VARP> parameterSets;
for (auto p : parameters) {
parameterSets.insert(p);
}
auto varmap = gradCommon(outputs, parameterSets, backwardMap);
std::vector<Express::VARP> res;
std::vector<Express::VARP> resDiff;
for (int i=0; i<parameters.size(); ++i) {
auto iter = varmap.find(parameters[i]);
if (iter != varmap.end()) {
res.push_back(iter->first);
resDiff.push_back(iter->second);
}
}
return std::make_pair(res, resDiff);
}
std::map<Express::VARP, Express::VARP> OpGrad::gradCommon(std::vector<Express::VARP> outputs, const std::set<Express::VARP>& parameters, std::map<EXPRP, std::vector<VARP>>& backwardMap, const std::vector<std::string> blockName) {
init();
auto executeOrder = Variable::getExecuteOrder(outputs);
for (auto iter = executeOrder.rbegin(); iter != executeOrder.rend(); iter++) {
auto expr = *iter;
auto& inputs = expr->inputs();
if (backwardMap.find(expr) == backwardMap.end()) {
continue;
}
if (nullptr == expr->get()) {
continue;
}
auto grad = OpGrad::get(expr->get()->type());
#ifdef MNN_TRAIN_DEBUG
MNN_PRINT("Grad for %s, %s\n", expr->name().c_str(), MNN::EnumNameOpType(expr->get()->type()));
#endif
if (nullptr == grad) {
#ifdef MNN_TRAIN_DEBUG
MNN_PRINT("Can't grad for %s, %s\n", expr->name().c_str(), MNN::EnumNameOpType(expr->get()->type()));
#endif
continue;
}
auto inputGrad = grad->onGrad(expr, backwardMap[expr]);
if (!expr->name().empty()) {
for (int v=0; v<inputGrad.size(); ++v) {
if (inputGrad[v].get() != nullptr) {
inputGrad[v]->setName("grad::" + expr->name() + std::to_string(v));
}
}
}
auto empty = true;
for (auto grad : inputGrad) {
if (nullptr != grad) {
empty = false;
break;
}
}
if (empty) {
#ifdef MNN_TRAIN_DEBUG
MNN_PRINT("Can't grad for %s, %d\n", expr->name().c_str(), expr->get()->type());
#endif
continue;
}
if (!blockName.empty()) {
if (std::find(blockName.begin(), blockName.end(), expr->name()) != blockName.end()) {
for (int ii = 0; ii <inputGrad.size(); ii++) {
inputGrad[ii] = nullptr;
}
continue;
}
}
#ifdef MNN_TRAIN_DEBUG
for (int i = 0; i < inputGrad.size(); ++i) {
if (nullptr == inputGrad[i]) {
continue;
}
auto info = inputGrad[i]->getInfo();
if (nullptr == info) {
MNN_ERROR("Grad error for %s, %d\n", expr->name().c_str(), expr->get()->type());
break;
}
}
#endif
MNN_ASSERT(inputGrad.size() <= inputs.size());
for (int i = 0; i < inputGrad.size(); ++i) {
auto inputExpr = inputs[i]->expr().first;
auto index = inputs[i]->expr().second;
auto backward = inputGrad[i];
if (nullptr == backward) {
continue;
}
if (backwardMap.find(inputExpr) == backwardMap.end()) {
backwardMap.insert(std::make_pair(inputExpr, std::vector<VARP>(inputExpr->outputSize())));
}
auto& inputVarMap = backwardMap[inputExpr];
if (nullptr == inputVarMap[index]) {
inputVarMap[index] = backward;
} else {
inputVarMap[index] = _Add(inputVarMap[index], backward);
}
}
}
std::map<Express::VARP, Express::VARP> grads;
std::map<Expr*, VARP> parametersExpr;
for (auto p : parameters) {
parametersExpr.insert(std::make_pair(p->expr().first.get(), p));
}
for (auto iter : backwardMap) {
auto expr = iter.first.get();
if (parametersExpr.find(expr) != parametersExpr.end()) {
auto parameter = parametersExpr[expr];
grads[parameter] = iter.second[parameter->expr().second];
}
}
// MNN_PRINT("Grad: %d <- %d\n", grads.size(), parameters.size());
return grads;
}
} // namespace MNN