Merge pull request #7754 from tonyyang-svail/7724

Make Parallel.Do support sparse gradients 

paddle/operators/parallel_do_op.cc

@@ -31,6 +31,7 @@ static constexpr char kParallelScopes[] = "parallel_scopes";
 static constexpr char kParallelBlock[] = "sub_block";
 
 using LoDTensor = framework::LoDTensor;
+using SelectedRows = framework::SelectedRows;
 
 static void SplitTensorAndMoveTensorToScopes(
     const framework::Scope &scope, std::vector<framework::Scope *> *sub_scopes,
@@ -64,6 +65,30 @@ static void SplitTensorAndMoveTensorToScopes(
   }
 }
 
+inline void CopyOrShare(const framework::Variable &src,
+                        const platform::Place &dst_place,
+                        framework::Variable *dst) {
+  if (src.IsType<LoDTensor>()) {
+    if (src.Get<LoDTensor>().place() == dst_place) {
+      dst->GetMutable<LoDTensor>()->ShareDataWith(src.Get<LoDTensor>());
+    } else {
+      Copy(src.Get<LoDTensor>(), dst_place, dst->GetMutable<LoDTensor>());
+    }
+  } else if (src.IsType<SelectedRows>()) {
+    auto &src_sr = src.Get<SelectedRows>();
+    auto *dst_sr = dst->GetMutable<SelectedRows>();
+    dst_sr->set_rows(src_sr.rows());
+    dst_sr->set_height(src_sr.height());
+    if (src_sr.value().place() == dst_place) {
+      dst_sr->mutable_value()->ShareDataWith(src_sr.value());
+    } else {
+      Copy(src_sr.value(), dst_place, dst_sr->mutable_value());
+    }
+  } else {
+    PADDLE_THROW("Expect LoDTensor/SelectedRows, get %s", src.Type().name());
+  }
+}
+
 void WaitOnPlace(const platform::Place place) {
   platform::DeviceContextPool &pool = platform::DeviceContextPool::Instance();
   auto &dev_ctx = *pool.Get(place);
@@ -210,30 +235,30 @@ class ParallelDoGradOp : public framework::OperatorBase {
     }
     WaitOnPlaces(places);
 
-    // merge grad
+    AccumulateGrad(scope, place, sub_scopes, places);
+  }
+
+  void AccumulateGrad(const framework::Scope &scope,
+                      const platform::Place &place,
+                      const std::vector<framework::Scope *> &sub_scopes,
+                      const platform::PlaceList &places) const {
     for (auto &s : Outputs(framework::GradVarName(kParameters))) {
-      auto &result = sub_scopes[0]->FindVar(s)->Get<LoDTensor>();
       std::string tmp_name;
-      auto *tmp = sub_scopes[0]->Var(&tmp_name)->GetMutable<LoDTensor>();
+      auto *tmp = sub_scopes[0]->Var(&tmp_name);
 
       for (size_t i = 1; i < sub_scopes.size(); ++i) {
-        auto &tensor_to_merge = sub_scopes[i]->FindVar(s)->Get<LoDTensor>();
-        if (!(places[i] == places[0])) {
-          framework::Copy(tensor_to_merge, places[0], tmp);
-          WaitOnPlace(places[0]);
-        } else {
-          tmp->ShareDataWith(tensor_to_merge);
-        }
+        CopyOrShare(*sub_scopes[i]->FindVar(s), places[0], tmp);
+        WaitOnPlace(places[0]);
 
         auto sum_op = framework::OpRegistry::CreateOp(
             "sum", {{"X", {s, tmp_name}}}, {{"Out", {s}}},
             framework::AttributeMap{});
+        VLOG(3) << sum_op->DebugStringEx(sub_scopes[0]);
         sum_op->Run(*sub_scopes[0], places[0]);
         WaitOnPlace(places[0]);
       }
 
-      VLOG(3) << result;
-      framework::Copy(result, place, scope.FindVar(s)->GetMutable<LoDTensor>());
+      CopyOrShare(*sub_scopes[0]->FindVar(s), place, scope.FindVar(s));
     }
     WaitOnPlaces(places);
   }
@@ -289,7 +314,7 @@ class ParallelDoGradOpShapeInference : public framework::InferShapeBase {
 
     PADDLE_ENFORCE(ctx->HasInputs(kParameters));
     PADDLE_ENFORCE(ctx->HasOutputs(framework::GradVarName(kParameters)));
-    PADDLE_ENFORCE(ctx->HasInput(kInputs));
+    PADDLE_ENFORCE(ctx->HasInputs(kInputs));
 
     for (auto &s : output) {
       PADDLE_ENFORCE(ctx->HasInputs(s));

python/paddle/v2/fluid/layers/control_flow.py

@@ -289,6 +289,7 @@ class ParallelDo(object):
                 for in_var_name in op.input(iname):
                     if in_var_name not in local_inputs:
                         params.append(in_var_name)
+        params = list(set(params))
 
         return [parent_block.var(name) for name in params]