MulticlassLossVariable.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

// 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 SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
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/* *******************************************************      
   * $Id: MulticlassLossVariable.cc,v 1.5 2004/04/27 15:58:16 morinf Exp $
   * This file is part of the PLearn library.
   ******************************************************* */

#include "MulticlassLossVariable.h"

namespace PLearn {
using namespace std;


PLEARN_IMPLEMENT_OBJECT(MulticlassLossVariable, 
                        "ONE LINE DESCR",
                        "NO HELP");

MulticlassLossVariable::MulticlassLossVariable(Variable* netout, Variable* target)
  : inherited(netout,target,1,1)
{
    build_();
}

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

void
MulticlassLossVariable::build_()
{
    if (input1 && input2) {
        // input1 and input2 are (respectively) netout and target from constructor
        if(input1->size() != input2->size())
            PLERROR("In MulticlassLossVariable: netout and target must the same size");
    }
}


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


void MulticlassLossVariable::fprop()
{
  real cost = 0.0;
  for (int i=0; i<input1->size(); i++)
  {
    real output = input1->valuedata[i];
    real target = input2->valuedata[i];
    cost += (target==1) ? output<0.5 : output>0.5;
  }
  valuedata[0] = cost;
}



} // end of namespace PLearn

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