DeterminantVariable.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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/* *******************************************************      
   * $Id: DeterminantVariable.cc,v 1.5 2004/04/27 15:58:16 morinf Exp $
   * This file is part of the PLearn library.
   ******************************************************* */

#include "DeterminantVariable.h"

namespace PLearn {
using namespace std;

PLEARN_IMPLEMENT_OBJECT(DeterminantVariable,
                        "The argument must be a square matrix Var and the result is its determinant",
                        "NO HELP");

DeterminantVariable::DeterminantVariable(Var m)
  : inherited(m,1,1) 
{
    build_();
}

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

void
DeterminantVariable::build_()
{
    if (input && (input->width() != input->length()))
        PLERROR("Max2Variable: parent(%d,%d) must be a square matrix",
                input->length() != input->width());
}


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


void DeterminantVariable::fprop()
{
  valuedata[0] = det(input->matValue);
}


void DeterminantVariable::bprop()
{
  PLERROR("DeterminantVariable::bprop not implemented yet");
}


void DeterminantVariable::symbolicBprop()
{
  PLERROR("DeterminantVariable::symbolicBprop not implemented yet");
}



} // end of namespace PLearn

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