// cudamatrix/cu-rand.h

// Copyright 2012  Karel Vesely

// 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_CUDAMATRIX_CU_RAND_H_
#define KALDI_CUDAMATRIX_CU_RAND_H_


#include "cudamatrix/cu-matrix.h"
#include "base/kaldi-math.h"

namespace kaldi {


template<typename Real> 
class CuRand {
 public:

  CuRand(): z1_(NULL), z2_(NULL), z3_(NULL), z4_(NULL), state_size_(0) { }

  ~CuRand();
  
  /// on demand seeding of all the buffers
  void SeedGpu(MatrixIndexT state_size);

  /// fill with numbers drawn from uniform distribution on [0, 1]
  void RandUniform(CuMatrixBase<Real> *tgt);
  /// fill with normal random numbers
  void RandGaussian(CuMatrixBase<Real> *tgt);
  void RandGaussian(CuVectorBase<Real> *tgt);

  /// align probabilities to discrete 0/1 states (use uniform samplig)
  void BinarizeProbs(const CuMatrix<Real> &probs, CuMatrix<Real> *states);
  /// add gaussian noise to each element
  void AddGaussNoise(CuMatrix<Real> *tgt, Real gscale = 1.0);

 private:
  /// seed one buffer on the GPU.  If state_size == 0, just frees any
  /// existing buffers.
  void SeedBuffer(MatrixIndexT state_size, uint32 **tgt);
   
 private:

  // CANNOT DEFINE CuMatrix<uint32>, 
  // CuMatrix has back-off Matrix which cannot hold integers. 
  // The inner state of random number generator will be in 
  // a raw buffer with the size of the current matrix. 
  //
  // On-demand seeding is used to get the correct size 
  // of the state buffer z1,z2,z3,z4
  
  /// Inner state of the ``grid-like'' random number generator
  uint32 *z1_, *z2_, *z3_, *z4_; 
  int32 state_size_; ///< size of the buffers
  
  CuMatrix<Real> tmp_; ///< auxiliary matrix
};


} // namsepace

#endif