// gmm/diag-gmm-normal.cc

// Copyright 2009-2011  Microsoft Corporation;  Saarland University;
//                      Yanmin Qian

// 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 <algorithm>
#include <limits>
#include <string>
#include <vector>

#include "gmm/diag-gmm-normal.h"
#include "gmm/diag-gmm.h"

namespace kaldi {

void DiagGmmNormal::Resize(int32 nmix, int32 dim) {
  KALDI_ASSERT(nmix > 0 && dim > 0);

  if (weights_.Dim() != nmix)
    weights_.Resize(nmix);

  if (vars_.NumRows() != nmix ||
      vars_.NumCols() != dim)
    vars_.Resize(nmix, dim);

  if (means_.NumRows() != nmix ||
      means_.NumCols() != dim)
    means_.Resize(nmix, dim);
}

void DiagGmmNormal::CopyFromDiagGmm(const DiagGmm &diaggmm) {
  int32 num_comp = diaggmm.weights_.Dim(), dim = diaggmm.Dim();
  Resize(num_comp, dim);

  weights_.CopyFromVec(diaggmm.weights_);
  vars_.CopyFromMat(diaggmm.inv_vars_);
  vars_.InvertElements();
  means_.CopyFromMat(diaggmm.means_invvars_);
  means_.MulElements(vars_);
}

void DiagGmmNormal::CopyToDiagGmm(DiagGmm *diaggmm, GmmFlagsType flags) const {
    KALDI_ASSERT((static_cast<int32>(diaggmm->Dim()) == means_.NumCols())
                 && (static_cast<int32>(diaggmm->weights_.Dim()) == weights_.Dim()));
    
    DiagGmmNormal oldg(*diaggmm);

    if (flags & kGmmWeights)
      diaggmm->weights_.CopyFromVec(weights_);

    if (flags & kGmmVariances) {
      diaggmm->inv_vars_.CopyFromMat(vars_);
      diaggmm->inv_vars_.InvertElements();

      // update the mean related natural part with the old mean, if necessary
      if (!(flags & kGmmMeans)) {
        diaggmm->means_invvars_.CopyFromMat(oldg.means_);
        diaggmm->means_invvars_.MulElements(diaggmm->inv_vars_);
      }
    }

    if (flags & kGmmMeans) {
      diaggmm->means_invvars_.CopyFromMat(means_);
      diaggmm->means_invvars_.MulElements(diaggmm->inv_vars_);
    }

    diaggmm->valid_gconsts_ = false;
}

}  // End namespace kaldi