diff --git a/paddle/api/Arguments.cpp b/paddle/api/Arguments.cpp
index a3f4bfffc9f074900ebcc52876c04bbfc0e570b2..d49b189e253f7a0792fe3f1fe7c8fdbb7071acd4 100644
--- a/paddle/api/Arguments.cpp
+++ b/paddle/api/Arguments.cpp
@@ -144,9 +144,7 @@ void Arguments::setSlotSequenceDim(size_t idx, IVector* vec) throw(RangeError) {
   a.cpuSequenceDims = m->cast<paddle::IVector>(vec->getSharedPtr());
 }
 
-float Arguments::sumCosts() const {
-  return paddle::Argument::sumCosts(m->outputs);
-}
+float Arguments::sum() const { return paddle::Argument::sum(m->outputs); }
 
 int64_t Arguments::getBatchSize(size_t idx) const throw(RangeError) {
   auto& a = m->getArg(idx);
diff --git a/paddle/api/PaddleAPI.h b/paddle/api/PaddleAPI.h
index 762f86ac79461558b6a2eb7105ffd05961f5d3e2..c4f5dca26cc6a5e9fdd23ee27b594ced29a25c7a 100644
--- a/paddle/api/PaddleAPI.h
+++ b/paddle/api/PaddleAPI.h
@@ -453,7 +453,7 @@ public:
                                         IVector* vec) throw(RangeError);
   void setSlotSequenceDim(size_t idx, IVector* vec) throw(RangeError);
 
-  float sumCosts() const;
+  float sum() const;
 
 private:
   static Arguments* createByPaddleArgumentVector(void* ptr);
diff --git a/paddle/api/test/testArguments.py b/paddle/api/test/testArguments.py
index a04a805d7a64ef906c8388f1241b9ef823e4d9e0..9fe44de94ea6ddb71d2dfbb2243fc86ede0d0531 100644
--- a/paddle/api/test/testArguments.py
+++ b/paddle/api/test/testArguments.py
@@ -22,7 +22,7 @@ class TestArguments(unittest.TestCase):
         args = swig_paddle.Arguments.createArguments(1)
         args.setSlotValue(0, m)
 
-        self.assertAlmostEqual(27.0, args.sumCosts())
+        self.assertAlmostEqual(27.0, args.sum())
 
         mat = args.getSlotValue(0)
         assert isinstance(mat, swig_paddle.Matrix)
diff --git a/paddle/gserver/tests/LayerGradUtil.cpp b/paddle/gserver/tests/LayerGradUtil.cpp
index ae016e74eaa84f7c43a30c09c8c4577e25360c4e..7617af10ba719490d1b33dd297b070cd8c7c292c 100644
--- a/paddle/gserver/tests/LayerGradUtil.cpp
+++ b/paddle/gserver/tests/LayerGradUtil.cpp
@@ -24,7 +24,7 @@ real getCostSum(LayerPtr& testLayer, MatrixPtr weights) {
   if (weights) {
     outArgs[0].value->dotMul(*outArgs[0].value, *weights);
   }
-  return Argument::sumCosts(outArgs);
+  return Argument::sum(outArgs);
 }
 
 real getDiffAndPrint(real newCost1,
@@ -241,7 +241,7 @@ void testBatchState(LayerPtr testLayer,
 
     std::vector<Argument> args;
     args.push_back(out);
-    EXPECT_EQ(0, Argument::sumCosts(args)) << "testBatchState failed";
+    EXPECT_EQ(0, Argument::sum(args)) << "testBatchState failed";
     for (size_t seqId = 0; seqId < numSequences; ++seqId) {
       start[seqId] += seqLens[seqId];
     }
@@ -672,7 +672,7 @@ void testLayerGradKernel(TestConfig testConf,
     outArgs[0].value->dotMul(*testLayer->getOutput().value, *weights);
   }
 
-  real cost = Argument::sumCosts(outArgs);
+  real cost = Argument::sum(outArgs);
   LOG(INFO) << " cost " << cost;
   EXPECT_FALSE(std::isnan(cost));
 
diff --git a/paddle/parameter/Argument.h b/paddle/parameter/Argument.h
index 178c068b93ac5fc1e06200984f14da86069cf7e4..9ef44be0cb3b960db1e789f3f26bb66d1fe63c81 100644
--- a/paddle/parameter/Argument.h
+++ b/paddle/parameter/Argument.h
@@ -163,7 +163,7 @@ struct Argument {
                        : sequenceStartPositions->getData(false);
   }
 
-  static inline real sumCosts(const std::vector<Argument>& arguments) {
+  static inline real sum(const std::vector<Argument>& arguments) {
     real cost = 0;
     for (auto& arg : arguments) {
       if (arg.value) {
diff --git a/paddle/trainer/Tester.cpp b/paddle/trainer/Tester.cpp
index 13aa28ae5d9699d267858d48e46797c756487ddd..80664fa877b324af73e3e3effa11e46eac6294e2 100644
--- a/paddle/trainer/Tester.cpp
+++ b/paddle/trainer/Tester.cpp
@@ -208,7 +208,7 @@ real Tester::forwardOneBatch(const DataBatch& dataBatch,
     return 0.0;  // In this case, there is no meaning to calculate cost
   }
 
-  return Argument::sumCosts(outArgs);
+  return Argument::sum(outArgs);
 }
 
 void Tester::testOnePassBatch(int passId) {
diff --git a/paddle/trainer/Trainer.cpp b/paddle/trainer/Trainer.cpp
index bd84545375117b178d4324f0ad03f5bc35ae925d..b68e29cd5ea223272151e7a8b52d998832f47103 100644
--- a/paddle/trainer/Trainer.cpp
+++ b/paddle/trainer/Trainer.cpp
@@ -310,7 +310,7 @@ real Trainer::checkGradient() {
   std::vector<Argument> outArgs;
 
   trainerInternal_.getGradientMachine()->forward(inArgs, &outArgs, PASS_GC);
-  real cost = Argument::sumCosts(outArgs);
+  real cost = Argument::sum(outArgs);
   LOG(INFO) << "original cost=" << cost;
   trainerInternal_.getGradientMachine()->backward();
 
@@ -340,7 +340,7 @@ real Trainer::checkGradient() {
     parameter->getBuf(PARAMETER_VALUE)->copyFrom(newPara);
     parameter->setValueUpdated();
     trainerInternal_.getGradientMachine()->forward(inArgs, &outArgs, PASS_GC);
-    real newCost1 = Argument::sumCosts(outArgs);
+    real newCost1 = Argument::sum(outArgs);
 
     for (size_t i = 0; i < dim; ++i) {
       newp[i] = oldp[i] - step * d[i];
@@ -349,7 +349,7 @@ real Trainer::checkGradient() {
     parameter->getBuf(PARAMETER_VALUE)->copyFrom(newPara);
     parameter->setValueUpdated();
     trainerInternal_.getGradientMachine()->forward(inArgs, &outArgs, PASS_GC);
-    real newCost2 = Argument::sumCosts(outArgs);
+    real newCost2 = Argument::sum(outArgs);
 
     real trueDelta = 0.5 * (newCost1 - newCost2);
     real diff = (1e-20 + trueDelta) / (1e-20 + delta) - 1;
@@ -575,7 +575,7 @@ real Trainer::calcGradient(const DataBatch& dataBatch,
 
   trainerInternal_.getGradientMachine()->forwardBackward(
       inArgs, &outArgs, PASS_TRAIN);
-  real cost = Argument::sumCosts(outArgs);
+  real cost = Argument::sum(outArgs);
 
   offset = 0;
   for (auto& para : parameters) {
diff --git a/paddle/trainer/TrainerInternal.cpp b/paddle/trainer/TrainerInternal.cpp
index f3b465b444167d4624a5e99c30e1257eda53ca2c..4c5d4a0913aaf3a9932b3d67806378ece4245304 100644
--- a/paddle/trainer/TrainerInternal.cpp
+++ b/paddle/trainer/TrainerInternal.cpp
@@ -134,7 +134,7 @@ void TrainerInternal::trainOneBatch(int64_t batchId,
   real cost = 0;
   {
     REGISTER_TIMER("sumCost");
-    cost = Argument::sumCosts(*outArgs);
+    cost = Argument::sum(*outArgs);
   }
 
   if (batchId % intconfig_->log_period == 0) {