split scale-post.cc into scale-post.cc and compute-mce-scale.cc

git-svn-id: https://svn.code.sf.net/p/kaldi/code/sandbox/discrim@644 5e6a8d80-dfce-4ca6-a32a-6e07a63d50c8

src/bin/compute-mce-scale.cc

+// bin/scale-post.cc
+
+// Copyright 2009-2011 Chao Weng 
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+
+#include "base/kaldi-common.h"
+#include "util/common-utils.h"
+
+
+int main(int argc, char *argv[]) {
+  try {
+    using namespace kaldi;
+    typedef kaldi::int32 int32;  
+
+    const char *usage =
+        "compute the scale of MCE, which is used to scale posteriors\n"
+        "Usage: computer-mce-scale [option] num-score-rspecifier "
+        "den-score-rspecifier out-scale-wspecifier\n";
+    
+    ParseOptions po(usage);
+    kaldi::BaseFloat mce_alpha = 1.0, mce_beta = 0.0;
+    po.Register("mce-alpha", &mce_alpha, "alpha parameter for sigmoid");
+    po.Register("mce-beta", &mce_beta, "beta parameter for sigmoid");
+    po.Read(argc, argv);
+
+    if (po.NumArgs() != 3) {
+      po.PrintUsage();
+      exit(1);
+    }
+    
+    std::string num_score_rspecifier = po.GetArg(1);
+    std::string den_score_rspecifier = po.GetArg(2);
+    std::string scale_wspecifier = po.GetArg(3);
+
+    kaldi::SequentialBaseFloatReader num_score_reader(num_score_rspecifier);
+    kaldi::RandomAccessBaseFloatReader den_score_reader(den_score_rspecifier);
+    kaldi::BaseFloatWriter scale_writer(scale_wspecifier);
+   
+    int32 num_scaled = 0, num_no_score = 0;
+
+    for (; !num_score_reader.Done(); num_score_reader.Next()) {
+      std::string key = num_score_reader.Key();
+      kaldi::BaseFloat num_score = num_score_reader.Value();
+      num_score_reader.FreeCurrent();
+      if (!den_score_reader.HasKey(key)) {
+        num_no_score++;
+      } else {
+        //calculat the sigmoid scaling factor for MCE
+        // = \alpha * sigmoid(num - den) * (1 - sigmoid(num - den))
+        BaseFloat den_score = den_score_reader.Value(key);
+        BaseFloat score_difference = mce_alpha * (num_score - den_score) + mce_beta;
+        BaseFloat sigmoid_difference = 1.0 / (1.0 + exp(score_difference));
+        BaseFloat scale = mce_alpha * sigmoid_difference * (1 - sigmoid_difference);
+        scale_writer.Write(key, scale);
+        num_scaled++; 
+      }    
+    }
+    KALDI_LOG << num_scaled << " scales generated; " << num_no_score
+              << " had no num/den scores."; 
+    return (num_scaled != 0 ? 0 : 1);
+  } catch(const std::exception& e) {
+    std::cerr << e.what();
+    return -1;
+  }
+}