Expose the acoustic scale in decoder

fluid/DeepASR/decoder/post_decode_faster.cc

@@ -21,14 +21,15 @@ using fst::StdArc;
 
 Decoder::Decoder(std::string word_syms_filename,
                  std::string fst_in_filename,
-                 std::string logprior_rxfilename) {
+                 std::string logprior_rxfilename,
+                 kaldi::BaseFloat acoustic_scale) {
   const char* usage =
       "Decode, reading log-likelihoods (of transition-ids or whatever symbol "
       "is on the graph) as matrices.";
 
   kaldi::ParseOptions po(usage);
   binary = true;
-  acoustic_scale = 1.5;
+  this->acoustic_scale = acoustic_scale;
   allow_partial = true;
   kaldi::FasterDecoderOptions decoder_opts;
   decoder_opts.Register(&po, true);  // true == include obscure settings.

fluid/DeepASR/decoder/post_decode_faster.h

@@ -29,7 +29,8 @@ class Decoder {
 public:
   Decoder(std::string word_syms_filename,
           std::string fst_in_filename,
-          std::string logprior_rxfilename);
+          std::string logprior_rxfilename,
+          kaldi::BaseFloat acoustic_scale);
   ~Decoder();
 
   // Interface to accept the scores read from specifier and return

fluid/DeepASR/decoder/pybind.cc

@@ -23,7 +23,7 @@ PYBIND11_MODULE(post_decode_faster, m) {
   m.doc() = "Decoder for Deep ASR model";
 
   py::class_<Decoder>(m, "Decoder")
-      .def(py::init<std::string, std::string, std::string>())
+      .def(py::init<std::string, std::string, std::string, kaldi::BaseFloat>())
       .def("decode",
            (std::vector<std::string> (Decoder::*)(std::string)) &
                Decoder::decode,

fluid/DeepASR/infer_by_ckpt.py

@@ -106,6 +106,11 @@ def parse_args():
         type=str,
         default="./decoder/logprior",
         help="The log prior probs for training data. (default: %(default)s)")
+    parser.add_argument(
+        '--acoustic_scale',
+        type=float,
+        default=0.2,
+        help="Scaling factor for acoustic likelihoods. (default: %(default)f)")
     args = parser.parse_args()
     return args