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src/online/online-decodable.cc 2.57 KB
8dcb6dfcb   Yannick Estève   first commit
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  // online/online-decodable.cc
  
  // Copyright 2012 Cisco Systems (author: Matthias Paulik)
  
  //   Modifications to the original contribution by Cisco Systems made by:
  //   Vassil Panayotov
  
  // See ../../COPYING for clarification regarding multiple authors
  //
  // 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 "online/online-decodable.h"
  
  namespace kaldi {
  
  OnlineDecodableDiagGmmScaled::OnlineDecodableDiagGmmScaled(
      const AmDiagGmm &am, const TransitionModel &trans_model,
      const BaseFloat scale, OnlineFeatureMatrix *input_feats):  
        features_(input_feats), ac_model_(am),
        ac_scale_(scale), trans_model_(trans_model),
        feat_dim_(input_feats->Dim()), cur_frame_(-1) {
    if (!input_feats->IsValidFrame(0)) {
      // It's not safe to throw from a constructor, so please check
      // this condition yourself before reaching this point in the code.
      KALDI_ERR << "Attempt to initialize decodable object with empty "
                << "input: please check this before the initializer!";
    }
    int32 num_pdfs = trans_model_.NumPdfs();
    cache_.resize(num_pdfs, std::pair<int32,BaseFloat>(-1, 0.0));
  }
  
  void OnlineDecodableDiagGmmScaled::CacheFrame(int32 frame) {
    KALDI_ASSERT(frame >= 0);
    cur_feats_.Resize(feat_dim_);
    if (!features_->IsValidFrame(frame))
      KALDI_ERR << "Request for invalid frame (you need to check IsLastFrame, or, "
                << "for frame zero, check that the input is valid.";
    cur_feats_.CopyFromVec(features_->GetFrame(frame));
    cur_frame_ = frame;
  }
  
  BaseFloat OnlineDecodableDiagGmmScaled::LogLikelihood(int32 frame, int32 index) {
    if (frame != cur_frame_)
      CacheFrame(frame);
    int32 pdf_id = trans_model_.TransitionIdToPdf(index);
    if (cache_[pdf_id].first == frame)
      return cache_[pdf_id].second;
    BaseFloat ans = ac_model_.LogLikelihood(pdf_id, cur_feats_) * ac_scale_;
    cache_[pdf_id].first = frame;
    cache_[pdf_id].second = ans;
    return ans;
  }
  
  
  bool OnlineDecodableDiagGmmScaled::IsLastFrame(int32 frame) const {
    return !features_->IsValidFrame(frame+1);
  }
  
  } // namespace kaldi