#include <nnet-pdf-prior.h>

Collaboration diagram for PdfPrior:

Public Member Functions
	PdfPrior (const PdfPriorOptions &opts)
	Initialize pdf-prior from options. More...

void	SubtractOnLogpost (CuMatrixBase< BaseFloat > *llk)
	Subtract pdf priors from log-posteriors to get pseudo log-likelihoods. More...

Private Member Functions
	KALDI_DISALLOW_COPY_AND_ASSIGN (PdfPrior)

Private Attributes
BaseFloat	prior_scale_

CuVector< BaseFloat >	log_priors_

Detailed Description

Definition at line 59 of file nnet-pdf-prior.h.

Constructor & Destructor Documentation

◆ PdfPrior()

PdfPrior ( const PdfPriorOptions & opts )

explicit

Initialize pdf-prior from options.

Definition at line 26 of file nnet-pdf-prior.cc.

References VectorBase< Real >::Add(), VectorBase< Real >::ApplyLog(), PdfPriorOptions::class_frame_counts, Input::Close(), VectorBase< Real >::Dim(), rnnlm::i, KALDI_ASSERT, KALDI_ISFINITE, KALDI_LOG, PdfPrior::log_priors_, Input::OpenTextMode(), PdfPriorOptions::prior_floor, Vector< Real >::Read(), VectorBase< Real >::Scale(), Input::Stream(), and VectorBase< Real >::Sum().

     : prior_scale_(opts.prior_scale) {
   if (opts.class_frame_counts == "") {
     // class_frame_counts is empty, the PdfPrior is deactivated...
     // (for example when 'nnet-forward' generates bottleneck features)
     return;
   }
 
   KALDI_LOG << "Computing pdf-priors from : " << opts.class_frame_counts;
 
   Vector<double> frame_counts, rel_freq, log_priors;
   {
     Input in;
     in.OpenTextMode(opts.class_frame_counts);
     frame_counts.Read(in.Stream(), false);
     in.Close();
   }
 
   // get relative frequencies,
   rel_freq = frame_counts;
   rel_freq.Scale(1.0/frame_counts.Sum());
 
   // get the log-prior,
   log_priors = rel_freq;
   log_priors.Add(1e-20);
   log_priors.ApplyLog();
 
   // Make the priors for classes with low counts +inf (i.e. -log(0))
   // such that the classes have 0 likelihood (i.e. -inf log-likelihood).
   // We use sqrt(FLT_MAX) instead of -kLogZeroFloat to prevent NANs
   // from appearing in computation.
   int32 num_floored = 0;
   for (int32 i = 0; i < log_priors.Dim(); i++) {
     if (rel_freq(i) < opts.prior_floor) {
       log_priors(i) = sqrt(FLT_MAX);
       num_floored++;
     }
   }
   KALDI_LOG << "Floored " << num_floored << " pdf-priors "
             << "(hard-set to " << sqrt(FLT_MAX)
             << ", which disables DNN output when decoding)";
 
   // sanity check,
   KALDI_ASSERT(KALDI_ISFINITE(log_priors.Sum()));
 
   // push to GPU,
   log_priors_ = Vector<BaseFloat>(log_priors);
 }

Member Function Documentation

◆ KALDI_DISALLOW_COPY_AND_ASSIGN()

KALDI_DISALLOW_COPY_AND_ASSIGN ( PdfPrior )

private

◆ SubtractOnLogpost()

void SubtractOnLogpost ( CuMatrixBase< BaseFloat > * llk )

Subtract pdf priors from log-posteriors to get pseudo log-likelihoods.

Definition at line 76 of file nnet-pdf-prior.cc.

References CuMatrixBase< Real >::AddVecToRows(), KALDI_ERR, PdfPrior::log_priors_, CuMatrixBase< Real >::NumCols(), and PdfPrior::prior_scale_.

Referenced by main().

                                                              {
   if (log_priors_.Dim() == 0) {
     KALDI_ERR << "--class-frame-counts is empty: Cannot initialize priors "
               << "without the counts.";
   }
   if (log_priors_.Dim() != llk->NumCols()) {
     KALDI_ERR << "Dimensionality mismatch,"
               << " class_frame_counts " << log_priors_.Dim()
               << " pdf_output_llk " << llk->NumCols();
   }
   llk->AddVecToRows(-prior_scale_, log_priors_);
 }