IfThenElseVariable.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: IfThenElseVariable.cc,v 1.6 2004/04/27 16:04:13 morinf Exp $
   * This file is part of the PLearn library.
   ******************************************************* */

#include "IfThenElseVariable.h"
#include "Var_utils.h"

namespace PLearn {
using namespace std;


PLEARN_IMPLEMENT_OBJECT(IfThenElseVariable,
                        "Variable that represents the element-wise IF-THEN-ELSE",
                        "NO HELP");

IfThenElseVariable::IfThenElseVariable(Var IfVar, Var ThenVar, Var ElseVar)
    : inherited(IfVar & ThenVar & (VarArray)ElseVar,ThenVar->length(), ThenVar->width())
{
    build_();
}

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

void
IfThenElseVariable::build_()
{
    if (varray.size()) {
        if (varray[1]->length() != varray[2]->length() || varray[1]->width() != varray[2]->width())
            PLERROR("In IfThenElseVariable: ElseVar and ThenVar must have the same size");
        if (!varray[0]->isScalar() && (varray[0]->length() != varray[1]->length() || varray[0]->width() != varray[1]->width()))
            PLERROR("In IfThenElseVariable: IfVar must either be a scalar or have the same size as ThenVar and ElseVar");
    }
}

void IfThenElseVariable::recomputeSize(int& l, int& w) const
{
    if (varray.size()) {
        l = varray[1]->length();
        w = varray[1]->width();
    } else
        l = w = 0;
}

void IfThenElseVariable::fprop()
{
  if(If()->isScalar())
    {
      //bool test = (bool)If()->valuedata[0];
            // norman: replaced a bad cast with a better boolean conversion
            bool test = If()->valuedata[0] == 0 ? false : true;
      if (test)
        value << Then()->value;
      else
        value << Else()->value;
    }
  else
    {
      real* ifv = If()->valuedata;
      real* thenv = Then()->valuedata;
      real* elsev = Else()->valuedata;
      for (int k=0;k<nelems();k++)
        {
          //if ((bool)ifv[k])
          // norman: replaced a bad cast with a better boolean conversion
          if ( ifv[k] == 0 ? false:true )
            valuedata[k]=thenv[k];
          else
            valuedata[k]=elsev[k];
        }
    }
}


void IfThenElseVariable::bprop()
{
  if(If()->isScalar())
    {
      // bool test = (bool)If()->valuedata[0];
          // norman: replaced a bad cast with a better boolean conversion
          bool test = If()->valuedata[0] == 0 ? false : true;
      if (test)
        Then()->gradient += gradient;
      else
        Else()->gradient += gradient;
    }
  else
    {
      real* ifv = If()->valuedata;
      real* theng = Then()->gradientdata;
      real* elseg = Else()->gradientdata;
      for (int k=0;k<nelems();k++)
        {
          //if ((bool)ifv[k])
          // norman: replaced a bad cast with a better boolean conversion
          if ( ifv[k] == 0 ? false:true )
            theng[k] += gradientdata[k];
          else
            elseg[k] += gradientdata[k];
        }
    }
}


void IfThenElseVariable::symbolicBprop()
{
  Var zero(length(), width());
  Then()->accg(ifThenElse(If(), g, zero));
  Else()->accg(ifThenElse(If(), zero, g));
}


void IfThenElseVariable::rfprop()
{
  if (rValue.length()==0) resizeRValue();
  if(If()->isScalar())
    {
                  //bool test = (bool)If()->valuedata[0];
                  // norman: replaced a bad cast to a better boolean conversion
            bool test = If()->valuedata[0] == 0 ? false : true;
      if (test)
        rValue << Then()->rValue;
      else
        rValue << Else()->rValue;
    }
  else
    {
      real* ifv = If()->valuedata;
      real* rthenv = Then()->rvaluedata;
      real* relsev = Else()->rvaluedata;
      for (int k=0;k<nelems();k++)
        {
          //if ((bool)ifv[k])
          // norman: replaced a bad cast with a better boolean conversion
          if ( ifv[k] == 0 ? false:true )
            rvaluedata[k]=rthenv[k];
          else
            rvaluedata[k]=relsev[k];
        }
    }
}



} // end of namespace PLearn

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