[src] Log nnet3 computation to VLOG, not std::cout (#3072)

Author: kkm000

src/nnet3/decodable-simple-looped.cc

@@ -52,7 +52,6 @@ DecodableNnetSimpleLoopedInfo::DecodableNnetSimpleLoopedInfo(
   Init(opts, &(am_nnet->GetNnet()));
 }
 
-
 void DecodableNnetSimpleLoopedInfo::Init(
     const NnetSimpleLoopedComputationOptions &opts,
     Nnet *nnet) {
@@ -86,10 +85,8 @@ void DecodableNnetSimpleLoopedInfo::Init(
   CompileLooped(*nnet, opts.optimize_config, request1, request2, request3,
                 &computation);
   computation.ComputeCudaIndexes();
-  if (GetVerboseLevel() >= 3) {
-    KALDI_VLOG(3) << "Computation is:";
-    computation.Print(std::cerr, *nnet);
-  }
+  KALDI_VLOG(3) << "Computation is:\n"
+                << NnetComputationPrintInserter{computation, *nnet};
 }
 
 

src/nnet3/nnet-computation.h

@@ -514,17 +514,22 @@ struct NnetComputation {
   NnetComputation(): need_model_derivative(false) { }
 };
 
-
-
-
-// This operator is to print out the NnetComputation in a human-readable way, for
-// debugging purposes.
-// We don't give Read and Write functions to struct NnetComputation, because we
-// don't anticipate needing to write it to disk.
-std::ostream &operator << (std::ostream &os,
-                           NnetComputation &computation);
-
-
+// A helper class equipped with the stream insertion operator<< to print out
+// the NnetComputation in a human-readable way, with NnetComputation::Print(),
+// for debugging purposes, e.g.:
+//    KALDI_VLOG(3) << NnetComputationPrintInserter{mycomputation, mynet};
+struct NnetComputationPrintInserter {
+  const NnetComputation& computation;
+  const Nnet& nnet;
+  void Print(std::ostream& os) const {
+    computation.Print(os, nnet);
+  }
+  friend inline std::ostream &operator <<(std::ostream &os,
+                                          NnetComputationPrintInserter xhis) {
+    xhis.Print(os);
+    return os;
+  }
+};
 
 } // namespace nnet3
 } // namespace kaldi