ThresholdVMatrix.h

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// -*- C++ -*-

// PLearn (A C++ Machine Learning Library)
// Copyright (C) 1998 Pascal Vincent
// Copyright (C) 1999-2001 Pascal Vincent, Yoshua Bengio, Rejean Ducharme and University of Montreal
// Copyright (C) 2002 Pascal Vincent, Julien Keable, Xavier Saint-Mleux
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 
//  1. Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
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// This file is part of the PLearn library. For more information on the PLearn
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#ifndef ThresholdVMatrix_INC
#define ThresholdVMatrix_INC

#include "RowBufferedVMatrix.h"
#include "VMat.h"

namespace PLearn {
using namespace std;
 
/* A bit like OneHotVMatrix with a threshold level
 * instead.  The last column will become cold_value
 * if it was <= threshold, or hot_value if it was
 * > threshold.
 * N.B. the gt_threshold boolean value can be set
 * to true so that we get hot_value when 
 * val > threshold, or false for val >= threshold.
 */
class ThresholdVMatrix: public RowBufferedVMatrix
{
  typedef RowBufferedVMatrix inherited;

 protected:
  VMat underlying_distr;
  real threshold;
  real cold_value;
  real hot_value;
  bool gt_threshold;

 public:
  // ******************
  // *  Constructors  *
  // ******************
  ThresholdVMatrix(); 

  ThresholdVMatrix(VMat the_underlying_distr, real threshold_, real the_cold_value=0.0, real the_hot_value=1.0,
                  bool gt_threshold_= true);
  virtual void getNewRow(int i, const Vec& v) const;
  virtual void reset_dimensions() 
    { 
      underlying_distr->reset_dimensions(); 
      width_=underlying_distr->width(); 
      length_=underlying_distr->length(); 
    }
};

inline VMat thresholdVMat(VMat d, real threshold, real cold_value=0.0, real hot_value=1.0,
                         bool gt_threshold= true)
{ return new ThresholdVMatrix(d, threshold, cold_value, hot_value, gt_threshold); }

} // end of namespcae PLearn
#endif

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