Set detection output to NULL

paddle/gserver/layers/DetectionOutputLayer.cpp

@@ -139,8 +139,13 @@ void DetectionOutputLayer::forward(PassType passType) {
                                        allDecodedBBoxes,
                                        &allIndices);
 
-  numKept = numKept > 0 ? numKept : 1;
-  resetOutput(numKept, 7);
+  if (numKept > 0) {
+    resetOutput(numKept, 7);
+  } else {
+    MatrixPtr outV = getOutputValue();
+    outV = NULL;
+    return;
+  }
   MatrixPtr outV = getOutputValue();
   getDetectionOutput(confBuffer_->getData(),
                      numKept,

paddle/gserver/layers/DetectionUtil.cpp

@@ -536,7 +536,6 @@ void getDetectionOutput(const real* confData,
   MatrixPtr outBuffer;
   Matrix::resizeOrCreate(outBuffer, numKept, 7, false, false);
   real* bufferData = outBuffer->getData();
-  for (size_t i = 0; i < 7; i++) bufferData[i] = -1;
   size_t count = 0;
   for (size_t n = 0; n < batchSize; ++n) {
     for (map<size_t, vector<size_t>>::const_iterator it = allIndices[n].begin();