ClassificationLossVariable.cc

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// -*- C++ -*-

// PLearn (A C++ Machine Learning Library)
// Copyright (C) 1998 Pascal Vincent
// Copyright (C) 1999-2002 Pascal Vincent, Yoshua Bengio, Rejean Ducharme and University of Montreal
// Copyright (C) 2001-2002 Nicolas Chapados, Ichiro Takeuchi, Jean-Sebastien Senecal
// Copyright (C) 2002 Xiangdong Wang, Christian Dorion

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// modification, are permitted provided that the following conditions are met:
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//  1. Redistributions of source code must retain the above copyright
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/* *******************************************************      
   * $Id: ClassificationLossVariable.cc,v 1.5 2004/04/27 15:58:16 morinf Exp $
   * This file is part of the PLearn library.
   ******************************************************* */

#include "ClassificationLossVariable.h"
namespace PLearn {
using namespace std;



PLEARN_IMPLEMENT_OBJECT(ClassificationLossVariable,
                        "Indicator(classnum==argmax(netout))",
                        "NO HELP");

ClassificationLossVariable::ClassificationLossVariable(Variable* netout, Variable* classnum)
  : inherited(netout,classnum,1,1)
{
    build_();
}

void
ClassificationLossVariable::build()
{
    inherited::build();
    build_();
}

void
ClassificationLossVariable::build_()
{
    // input2 is classnum from constructor
    if (input2 && !input2->isScalar())
        PLERROR("In ClassificationLossVariable: classnum must be a scalar variable representing an index of netout (typically a class number)");
}

void ClassificationLossVariable::recomputeSize(int& l, int& w) const
{ l=1, w=1; }


void ClassificationLossVariable::fprop()
{
  int topscorepos = argmax(input1->value);
  int classnum = int(input2->valuedata[0]);
  valuedata[0] = (topscorepos==classnum ?0 :1);
}



} // end of namespace PLearn

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