text: // nnet2/nnet-limit-rank.h
  
  // Copyright 2012  Johns Hopkins University (author: Daniel Povey)
  
  // 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.
  
  #ifndef KALDI_NNET2_NNET_LIMIT_RANK_H_
  #define KALDI_NNET2_NNET_LIMIT_RANK_H_
  
  #include "nnet2/nnet-nnet.h"
  #include "util/table-types.h"
  #include "thread/kaldi-semaphore.h"
  #include "thread/kaldi-thread.h"
  #include "nnet2/nnet-update.h"
  
  namespace kaldi {
  namespace nnet2 {
  
  struct NnetLimitRankOpts {
    int32 num_threads;
    BaseFloat parameter_proportion;
    
    NnetLimitRankOpts(): num_threads(1), parameter_proportion(0.75) { }
  
    void Register(OptionsItf *po) {
      po->Register("num-threads", &num_threads, "Number of threads used for "
                   "rank-limiting operation; note, will never use more than "
                   "#layers.");
      po->Register("parameter-proportion", &parameter_proportion, "Proportion of "
                   "dimension of each transform to limit the rank to.");
    }  
  };
  
  
  /// This function limits the rank of each affine transform in the
  /// neural net, by zeroing out the smallest singular values.  The number of
  /// singular values to zero out is determined on a layer by layer basis, using
  /// "parameter_proportion" to set the proportion of parameters to remove.
  void LimitRankParallel(const NnetLimitRankOpts &opts,
                         Nnet *nnet);
  
  
  /// Also see the function LimitRankOfLastLayer in class Nnet.                            
  
  
  } // namespace nnet2
  } // namespace kaldi
  
  #endif // KALDI_NNET2_NNET_LIMIT_RANK_H_
  