add OpBase and unify with VarBase

test=develop

paddle/fluid/imperative/CMakeLists.txt

-cc_library(layer SRCS layer.cc)
+cc_library(layer SRCS layer.cc DEPS proto_desc)
 cc_library(tracer SRCS tracer.cc DEPS proto_desc)
 cc_library(engine SRCS engine.cc)

paddle/fluid/imperative/layer.h

@@ -15,6 +15,7 @@
 #pragma once
 
 #include <vector>
+#include "paddle/fluid/framework/op_desc.h"
 #include "paddle/fluid/framework/scope.h"
 #include "paddle/fluid/framework/var_desc.h"
 #include "paddle/fluid/platform/enforce.h"
@@ -22,21 +23,28 @@
 namespace paddle {
 namespace imperative {
 
-class VariableBase {
+class VarBase {
  public:
-  VariableBase() {}
-  virtual ~VariableBase() {}
+  VarBase() {}
+  virtual ~VarBase() {}
 
   framework::VarDesc* var_desc_;
 };
 
+class OpBase {
+ public:
+  OpBase() {}
+  virtual ~OpBase() {}
+
+  framework::OpDesc* op_desc_;
+};
+
 class Layer {
  public:
   virtual ~Layer() {}
 
-  virtual std::vector<VariableBase> Forward(
-      const std::vector<VariableBase>& inputs) {
-    std::vector<VariableBase> vars;
+  virtual std::vector<VarBase> Forward(const std::vector<VarBase>& inputs) {
+    std::vector<VarBase> vars;
     return vars;
   }
 

paddle/fluid/imperative/tracer.h

@@ -14,6 +14,7 @@
 
 #pragma once
 
+#include <map>
 #include <string>
 #include <vector>
 
@@ -21,6 +22,7 @@
 #include "paddle/fluid/framework/op_registry.h"
 #include "paddle/fluid/framework/scope.h"
 #include "paddle/fluid/imperative/engine.h"
+#include "paddle/fluid/imperative/layer.h"
 
 namespace paddle {
 namespace imperative {
@@ -29,11 +31,13 @@ class Tracer {
  public:
   Tracer() {}
 
-  void Trace(framework::OpDesc* op_desc) {
+  void Trace(OpBase* op, const std::map<std::string, VarBase*>& inputs,
+             const std::map<std::string, VarBase*>& outputs) {
+    framework::OpDesc* op_desc = op->op_desc_;
     LOG(ERROR) << "tracer tracing " << op_desc->Type();
     op_desc->InferShape(*block_);
     op_desc->InferVarType(block_);
-    std::unique_ptr<framework::OperatorBase> op =
+    std::unique_ptr<framework::OperatorBase> op_base =
         framework::OpRegistry::CreateOp(*op_desc);
     for (const std::string& vname : op_desc->InputArgumentNames()) {
       framework::Variable* var = scope_->Var(vname);
@@ -57,7 +61,7 @@ class Tracer {
         }
       }
     }
-    op->Run(*scope_, platform::CPUPlace());
+    op_base->Run(*scope_, platform::CPUPlace());
   }
 
   void SetScope(framework::Scope* scope) { scope_ = scope; }

paddle/fluid/pybind/imperative.h

@@ -26,9 +26,9 @@ class PyLayer : public imperative::Layer {
  public:
   using imperative::Layer::Layer;  // Inherit constructors
 
-  std::vector<imperative::VariableBase> Forward(
-      const std::vector<imperative::VariableBase>& inputs) override {
-    PYBIND11_OVERLOAD(std::vector<imperative::VariableBase>, Layer, Forward,
+  std::vector<imperative::VarBase> Forward(
+      const std::vector<imperative::VarBase>& inputs) override {
+    PYBIND11_OVERLOAD(std::vector<imperative::VarBase>, Layer, Forward,
                       inputs);  // NOLINT
   }
 

paddle/fluid/pybind/pybind.cc

@@ -101,21 +101,30 @@ PYBIND11_MODULE(core, m) {
 
   BindException(&m);
 
-  py::class_<imperative::VariableBase>(m, "VariableBase",
+  py::class_<imperative::VarBase>(m, "VarBase",
                                   R"DOC()DOC")
       .def_property(
           "desc",
-          [](const imperative::VariableBase &self) { return self.var_desc_; },
-          [](imperative::VariableBase &self, framework::VarDesc *var_desc) {
+          [](const imperative::VarBase &self) { return self.var_desc_; },
+          [](imperative::VarBase &self, framework::VarDesc *var_desc) {
             self.var_desc_ = var_desc;
           },
           py::return_value_policy::reference);
 
+  py::class_<imperative::OpBase>(m, "OpBase",
+                                 R"DOC()DOC")
+      .def_property(
+          "desc", [](const imperative::OpBase &self) { return self.op_desc_; },
+          [](imperative::OpBase &self, framework::OpDesc *op_desc) {
+            self.op_desc_ = op_desc;
+          },
+          py::return_value_policy::reference);
+
   py::class_<imperative::Layer, PyLayer /* <--- trampoline*/> layer(m, "Layer");
   layer.def(py::init<>())
       .def("forward",
            [](imperative::Layer &self,
-              const std::vector<imperative::VariableBase> &inputs) {
+              const std::vector<imperative::VarBase> &inputs) {
              return self.Forward(inputs);
            })
       .def("backward", &imperative::Layer::Backward);

python/paddle/fluid/framework.py

@@ -212,7 +212,7 @@ def _debug_string_(proto, throw_on_error=True):
     return proto.__str__()
 
 
-class Variable(core.VariableBase):
+class Variable(core.VarBase):
     """
     In Fluid, every input and output of an operator is a variable. In most
     cases, variables are used for holding different kinds of data or training
@@ -507,7 +507,7 @@ class OpProtoHolder(object):
         }
 
 
-class Operator(object):
+class Operator(core.OpBase):
     """
     In Fluid, all the operation are represented by Operator, and Operator
     is regarded as a build in an instruction of a Block. Users can use the
@@ -602,20 +602,20 @@ class Operator(object):
                     return True
             return False
 
-        if inputs is not None:
+        self.inputs = [] if not inputs else inputs
         for in_proto in proto.inputs:
-                found = find_name(inputs, in_proto.name)
+            found = find_name(self.inputs, in_proto.name)
             assert found or in_proto.dispensable, "Input {} not found".format(
                 in_proto.name)
 
             if found:
-                    in_args = inputs[in_proto.name]
+                in_args = self.inputs[in_proto.name]
                 if not isinstance(in_args, list):
                     in_args = [in_args]
                 if not in_proto.duplicable and len(in_args) > 1:
                     raise ValueError(
-                            "Input %s expects only one input, but %d are given."
-                            % (in_proto.name, len(in_args)))
+                        "Input %s expects only one input, but %d are given." %
+                        (in_proto.name, len(in_args)))
                 in_arg_names = []
                 for arg in in_args:
                     if isinstance(arg, six.string_types):
@@ -628,6 +628,7 @@ class Operator(object):
             else:
                 self.desc.set_input(in_proto.name, [])
 
+        self.outputs = [] if not outputs else outputs
         if outputs is not None:
             given = set()
             need = set()
@@ -1222,7 +1223,8 @@ class Block(object):
         if _in_imperative_mode():
             op_desc = core.OpDesc()
             op = Operator(block=self, desc=op_desc, *args, **kwargs)
-            _imperative_tracer().trace(op.desc)
+            sys.stderr.write('%s %s!!!\n' % (type(op.inputs), type(op.outputs)))
+            _imperative_tracer().trace(op, op.inputs, op.outputs)
             return
 
         op_desc = self.desc.append_op()