ByteMemoryVMatrix.cc

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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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// 
//  3. The name of the authors may not be used to endorse or promote
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//     permission.
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// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
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/* *******************************************************      
   * $Id: ByteMemoryVMatrix.cc,v 1.4 2004/04/05 22:48:12 morinf Exp $
   ******************************************************* */

#include "ByteMemoryVMatrix.h"

namespace PLearn {
using namespace std;

PLEARN_IMPLEMENT_OBJECT(ByteMemoryVMatrix, "ONE_LINE_DESCR", "ONE LINE HELP");

ByteMemoryVMatrix::ByteMemoryVMatrix()
  : data(0)
{
}

ByteMemoryVMatrix::ByteMemoryVMatrix(unsigned char* the_data,int the_length,int the_width, Vec the_scale)
  :inherited(the_length, the_width), data(the_data), scale(the_scale), offset_(the_scale.length())
{
  if (the_scale.length() != width_)
    PLERROR("ByteMemoryVMatrix: inconsistent arguments (scale(%d),n_col(%d))",
          the_scale.length(), width_);
}

ByteMemoryVMatrix::
ByteMemoryVMatrix(unsigned char* the_data,int the_length,int the_width, 
                          Vec the_scale, Vec the_offset)
  :VMatrix(the_length, the_width), data(the_data), 
   scale(the_scale), offset_(the_offset)
{
  if (the_scale.length() != width_ || the_offset.length()!=width_)
    PLERROR("ByteMemoryVMatrix: inconsistent arguments (scale(%d),offset(%d),n_col(%d))",
          the_scale.length(), the_offset.length(), width_);
}

ByteMemoryVMatrix::ByteMemoryVMatrix(unsigned char* the_data,int the_length,int the_width,
                            double the_scaling_factor,double the_offset)
  : VMatrix(the_length, the_width), data(the_data), 
   scale(the_width, the_scaling_factor), offset_(the_width, the_offset)
{
}

real ByteMemoryVMatrix::get(int i, int j) const
{
  return ( data[i*width()+j] + offset_[j] ) * scale[j];
}

void ByteMemoryVMatrix::getSubRow(int i, int j, Vec samplevec) const
{
  unsigned char* p = &data[i*width_];
  real *v = samplevec.data();
  real *s = scale.data();
  real *o = offset_.data();
  for (int jj=0; jj<samplevec.length(); jj++)
    v[jj] = s[j+jj] * (p[j+jj] + o[j+jj]);
}

} // end of namespcae PLearn

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