NistDB.cc

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// -*- C++ -*-

// PLearn (A C++ Machine Learning Library)
// Copyright (C) 1998 Pascal Vincent
// Copyright (C) 1999,2000 Pascal Vincent, Yoshua Bengio and University of Montreal
//

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//  1. Redistributions of source code must retain the above copyright
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//     products derived from this software without specific prior written
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// This file is part of the PLearn library. For more information on the PLearn
// library, go to the PLearn Web site at www.plearn.org



/* *******************************************************      
   * $Id: NistDB.cc,v 1.3 2004/02/26 06:39:03 nova77 Exp $
   * AUTHORS: Pascal Vincent
   * This file is part of the PLearn library.
   ******************************************************* */

#include "NistDB.h"

namespace PLearn {
using namespace std;


#define DO_RESCALE

NistDB::NistDB(bool train)
  :VMatrix(60000, 28*28+1)
{
  if(train)
    {
      imagef.open("/u/lisa/Database/MNIST/train-images-idx3-ubyte");
      labelf.open("/u/lisa/Database/MNIST/train-labels-idx1-ubyte");
      length_ = 60000;
    }
  else
    {
      //      imagef.open("/u/lisa/Database/MNIST/test-images.idx3-ubyte");
      //      labelf.open("/u/lisa/Database/MNIST/test-labels.idx1-ubyte");
      //      length_ = 60000;
      imagef.open("/u/lisa/Database/MNIST/t10k-images-idx3-ubyte");
      labelf.open("/u/lisa/Database/MNIST/t10k-labels-idx1-ubyte");
      length_ = 10000;
    }
  if(!imagef)
    PLERROR("In NistDB constructor could not open imagefile for reading");
  if(!labelf)
    PLERROR("In NistDB constructor could not open labelfile for reading");
}
  
real NistDB::get(int i, int j) const
{
#ifdef BOUNDCHECK
  if(i<0 || i>=length() || j<0 || j>=width())
    PLERROR("In NistDB::get OUT OF BOUNDS");
#endif
  if(j==width()-1) // then read from labelf
    {
      labelf.seekg(8+i);
      return real(labelf.get());
    }
  else // read from imagef
    {
      imagef.seekg(16+i*(28*28)+j);
#ifdef DO_RESCALE
      return real(imagef.get())/255.0;
#else
      return real(imagef.get());
#endif
    }
}
 
void NistDB::getSubRow(int i, int j, Vec v) const
{
#ifdef BOUNDCHECK
  if(i<0 || i>=length() || j<0 || j+v.length()>width())
    PLERROR("In NistDB::getSubRow OUT OF BOUNDS");
#endif
  
  int npixelstoread = v.length();
  if(j+v.length()==width())
    {
      labelf.seekg(8+i);
      v[v.length()-1] = real(labelf.get());
      npixelstoread--;
    }

  if(j<width()-1)
    {
      imagef.seekg(16+i*(28*28)+j);
#if __GNUC__ < 3 && !defined(WIN32)
      imagef.read(buf, npixelstoread);
#else
      imagef.read(reinterpret_cast<char*>(buf), npixelstoread);
#endif
      for(int k=0; k<npixelstoread; k++)
        {
#ifdef DO_RESCALE
          v[k] = real(buf[k])/255.0;
#else
          v[k] = real(buf[k]);
#endif
        }
    }
}









} // end of namespace PLearn

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