Simple Implementation

Author: reyoung

paddle/framework/operator.cc

@@ -35,16 +35,10 @@ ExecutionContext::GetEigenDevice<platform::GPUPlace, Eigen::GpuDevice>() const {
 
 std::string OperatorBase::Input(const std::string& name) const {
  auto& ins = Inputs(name);
- switch (ins.size()) {
- case 0:
- return kEmptyVarName;
- case 1:
- return ins[0];
- default:
- PADDLE_THROW("Op %s input %s should contain only one variable", type_,
- name);
- return "";
- }
+ PADDLE_ENFORCE_LE(ins.size(), 1UL,
+ "Op %s input %s should contain only one variable", type_,
+ name);
+ return ins.empty() ? kEmptyVarName : ins[0];
 }
 
 const std::vector<std::string>& OperatorBase::Inputs(
@@ -57,16 +51,10 @@ const std::vector<std::string>& OperatorBase::Inputs(
 
 std::string OperatorBase::Output(const std::string& name) const {
  auto& outs = Outputs(name);
- switch (outs.size()) {
- case 0:
- return kEmptyVarName;
- case 1:
- return outs[0];
- default:
- PADDLE_THROW("Op %s output %s should contain only one variable", type_,
- name);
- return "";
- }
+ PADDLE_ENFORCE_LE(outs.size(), 1UL,
+ "Op %s output %s should contain only one variable", type_,
+ name);
+ return outs.empty() ? kEmptyVarName : outs[0];
 }
 
 const std::vector<std::string>& OperatorBase::Outputs(

paddle/framework/operator.h

@@ -239,20 +239,12 @@ class InferShapeContext {
 
  const Variable* InputVar(const std::string& name) const {
  auto ipt = op_.Input(name);
- if (ipt == kEmptyVarName) {
- return nullptr;
- } else {
- return scope_.FindVar(ipt);
- }
+ return ipt == kEmptyVarName ? nullptr : scope_.FindVar(ipt);
  }
 
  Variable* OutputVar(const std::string& name) const {
  auto opt = op_.Output(name);
- if (opt == kEmptyVarName) {
- return nullptr;
- } else {
- return scope_.FindVar(opt);
- }
+ return opt == kEmptyVarName ? nullptr : scope_.FindVar(opt);
  }
 
  const std::vector<const Variable*> MultiInputVar(
@@ -262,8 +254,8 @@ class InferShapeContext {
  res.reserve(names.size());
  std::transform(names.begin(), names.end(), std::back_inserter(res),
  [this](const std::string& name) {
- return name != kEmptyVarName ? scope_.FindVar(name)
- : nullptr;
+ return name == kEmptyVarName ? nullptr
+ : scope_.FindVar(name);
  });
  return res;
  }
@@ -274,8 +266,8 @@ class InferShapeContext {
  res.reserve(names.size());
  std::transform(names.begin(), names.end(), std::back_inserter(res),
  [this](const std::string& name) {
- return name != kEmptyVarName ? scope_.FindVar(name)
- : nullptr;
+ return name == kEmptyVarName ? nullptr
+ : scope_.FindVar(name);
  });
  return res;
  }