refine _grad_ivar (#49787)

paddle/fluid/pybind/eager_method.cc

@@ -1893,6 +1893,21 @@ static PyObject* tensor_data_ptr(TensorObject* self,
   EAGER_CATCH_AND_THROW_RETURN_NULL
 }
 
+static PyObject* tensor__grad_ivar(TensorObject* self,
+                                   PyObject* args,
+                                   PyObject* kwargs) {
+  EAGER_TRY
+  VLOG(6) << "Get grad for tensor: " << self->tensor.name();
+  auto meta = egr::EagerUtils::nullable_autograd_meta(self->tensor);
+  VLOG(6) << meta << " initialized: " << meta->Grad().initialized();
+  if (meta && meta->Grad().initialized()) {
+    return ToPyObject(meta->Grad());
+  } else {
+    RETURN_PY_NONE
+  }
+  EAGER_CATCH_AND_THROW_RETURN_NULL
+}
+
 #if defined(PADDLE_WITH_CUDA)
 static PyObject* tensor_method__uva(TensorObject* self,
                                     PyObject* args,
@@ -2152,6 +2167,10 @@ PyMethodDef variable_methods[] = {
      (PyCFunction)(void (*)(void))tensor_data_ptr,
      METH_VARARGS | METH_KEYWORDS,
      NULL},
+    {"_grad_ivar",
+     (PyCFunction)(void (*)(void))tensor__grad_ivar,
+     METH_VARARGS | METH_KEYWORDS,
+     NULL},
 #if defined(PADDLE_WITH_CUDA)
     {"_tensor_uva",
      (PyCFunction)(void (*)(void))tensor_method__uva,

python/paddle/fluid/dygraph/varbase_patch_methods.py

@@ -856,13 +856,6 @@ def monkey_patch_varbase():
                 # Call c++ func __setitem_varbase__ to speedup.
                 return self.__setitem_varbase__(item, value)
 
-    @framework.dygraph_only
-    def _grad_ivar(self):
-        if self.grad is not None:
-            if self.grad._is_initialized():
-                return self.grad
-        return None
-
     @framework.dygraph_only
     def _set_grad_ivar(self, value):
         if isinstance(self, EagerParamBase):
@@ -1060,7 +1053,6 @@ def monkey_patch_varbase():
             setattr(core.VarBase, method_name, method)
 
     if framework._in_eager_mode_:
-        setattr(core.eager.Tensor, "_grad_ivar", _grad_ivar)
         setattr(core.eager.Tensor, "_set_grad_ivar", _set_grad_ivar)
         setattr(core.eager.Tensor, "value", value)
         setattr(core.eager.Tensor, "cpu", cpu)