From cb95587feb6e32c8595d02e76e58aa69a96b5035 Mon Sep 17 00:00:00 2001
From: dongzhihong <dzhwinter@gmail.com>
Date: Wed, 19 Jul 2017 14:28:29 +0800
Subject: [PATCH] "ignore some gradient of specific op"

---
 paddle/framework/op_proto.proto |  6 ++++++
 paddle/framework/op_registry.h  | 16 ++++++++++------
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/paddle/framework/op_proto.proto b/paddle/framework/op_proto.proto
index 596b8588e..366c84e53 100644
--- a/paddle/framework/op_proto.proto
+++ b/paddle/framework/op_proto.proto
@@ -84,6 +84,11 @@ message VarProto {
     //   "temporary_index": [1]
     // }
     optional bool temporary = 4 [default=false];
+
+    // The gradient of operator can be ignored immediately
+    // e.g. operator AddOp, y = x1 + x2, the gradient of dy/dx1, dy/dx2
+    // can be ignored for the future optimized on graph.
+    optional bool ignore_gradient = 6;
 }
 
 // Op protocol message for 3rd-party language binding.
@@ -105,4 +110,5 @@ message OpProto {
 
     // The type of that Op.
     required string type = 5;
+
 }
diff --git a/paddle/framework/op_registry.h b/paddle/framework/op_registry.h
index 6ba0784f1..dded0ad33 100644
--- a/paddle/framework/op_registry.h
+++ b/paddle/framework/op_registry.h
@@ -74,25 +74,29 @@ class OpProtoAndCheckerMaker {
 
  protected:
   void AddInput(const std::string& name, const std::string& comment,
-                bool multiple = false) {
+                bool multiple = false, bool ignore_gradient = false) {
     auto input = proto_->mutable_inputs()->Add();
     *input->mutable_name() = name;
     *input->mutable_comment() = comment;
+    *input->set_ignore_gradient(ignore_gradient);
     input->set_multiple(multiple);
     if (multiple) {
       SetHasMultipleInput();
     }
   }
 
-  void AddInputs(const std::string& name, const std::string& comment) {
-    AddInput(name, comment, true);
+  void AddInputs(const std::string& name, const std::string& comment,
+                 bool ignore_gradient = false) {
+    AddInput(name, comment, true, ignore_gradient);
   }
 
   void AddOutput(const std::string& name, const std::string& comment,
-                 bool temporary = false, bool multiple = false) {
+                 bool temporary = false, bool multiple = false,
+                 bool ignore_gradient = false) {
     auto output = proto_->mutable_outputs()->Add();
     *output->mutable_name() = name;
     *output->mutable_comment() = comment;
+    *output->set_ignore_gradient(ignore_gradient);
     output->set_multiple(multiple);
     if (multiple) {
       SetHasMultipleOutput();
@@ -104,8 +108,8 @@ class OpProtoAndCheckerMaker {
   }
 
   void AddOutputs(const std::string& name, const std::string& comment,
-                  bool temporary = false) {
-    AddOutput(name, comment, temporary, true);
+                  bool temporary = false, bool ignore_gradient = false) {
+    AddOutput(name, comment, temporary, true, ignore_gradient);
   }
 
   template <typename T>
-- 
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