Var_operators.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.
// 
//  2. Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
// 
//  3. The name of the authors may not be used to endorse or promote
//     products derived from this software without specific prior written
//     permission.
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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: Var_operators.cc,v 1.2 2004/02/20 21:11:54 chrish42 Exp $
   * This file is part of the PLearn library.
   ******************************************************* */

#include "Var_operators.h"

#include "PlusConstantVariable.h"
#include "PlusScalarVariable.h"
#include "PlusRowVariable.h"
#include "PlusColumnVariable.h"
#include "PlusVariable.h"

#include "MinusScalarVariable.h"
#include "NegateElementsVariable.h"
#include "MinusRowVariable.h"
#include "MinusColumnVariable.h"
#include "MinusVariable.h"

#include "TimesConstantVariable.h"
#include "TimesScalarVariable.h"
#include "TimesColumnVariable.h"
#include "TimesRowVariable.h"
#include "TimesVariable.h"

#include "InvertElementsVariable.h"
#include "DivVariable.h"

#include "EqualVariable.h"

namespace PLearn {
using namespace std;

Var operator+(Var v, real cte)
{ return new PlusConstantVariable(v,cte); }

Var operator+(real cte, Var v)
{ return new PlusConstantVariable(v,cte); }

Var operator-(Var v, real cte)
{ return new PlusConstantVariable(v,-cte); }

Var operator+(Var v1, Var v2)
{ 
  if(v2->isScalar())
    return new PlusScalarVariable(v1,v2);
  else if(v1->isScalar())
    return new PlusScalarVariable(v2,v1);
  else if(v2->isRowVec())
    return new PlusRowVariable(v1,v2);
  else if(v1->isRowVec())
    return new PlusRowVariable(v2,v1);
  else if(v2->isColumnVec())
    return new PlusColumnVariable(v1,v2);
  else if(v1->isColumnVec())
    return new PlusColumnVariable(v2,v1);
  else
    return new PlusVariable(v1,v2);
}

void operator+=(Var& v1, const Var& v2)
{
  if (!v2.isNull())
  {
    if (v1.isNull())
      v1 = v2;
    else 
      v1 = v1 + v2;
  }
}

Var operator-(Var v1, Var v2)
{ 
  if(v2->isScalar())
    return new MinusScalarVariable(v1,v2);
  else if(v1->isScalar())
    return new PlusScalarVariable(new NegateElementsVariable(v2), v1);
  else if(v2->isRowVec())
    return new MinusRowVariable(v1,v2);
  else if(v1->isRowVec())
    return new NegateElementsVariable(new MinusRowVariable(v2,v1));
  else if(v2->isColumnVec())
    return new MinusColumnVariable(v1,v2);
  else if(v1->isColumnVec())
    return new PlusColumnVariable(new NegateElementsVariable(v2), v1);
  else
    return new MinusVariable(v1,v2);
}

Var operator-(Var v)
{ return new NegateElementsVariable(v); }

void operator-=(Var& v1, const Var& v2)
{
  if (!v2.isNull())
  {
    if (v1.isNull())
      v1 = -v2;
    else
      v1 = v1 - v2;
  }
}

Var operator-(real cte, Var v)
{ return new PlusConstantVariable(new NegateElementsVariable(v),cte); }



Var operator*(Var v, real cte)
{ return new TimesConstantVariable(v,cte); }

Var operator*(real cte, Var v)
{ return new TimesConstantVariable(v,cte); }


Var operator*(Var v1, Var v2)
{ 
  if(v2->isScalar())
    return new TimesScalarVariable(v1,v2);
  else if(v1->isScalar())
    return new TimesScalarVariable(v2,v1);
  else if(v2->isColumnVec())
    return new TimesColumnVariable(v1,v2);
  else if(v1->isColumnVec())
    return new TimesColumnVariable(v2,v1);
  else if(v2->isRowVec())
    return new TimesRowVariable(v1,v2);
  else if(v1->isRowVec())
    return new TimesRowVariable(v2,v1);
  else 
    return new TimesVariable(v1,v2); 
}

Var operator/(Var v, real cte)
{ return new TimesConstantVariable(v, 1.0/cte); }

Var operator/(real cte, Var v)
{
  if(cte==1.0)
    return invertElements(v);
  else
    return cte*invertElements(v);
}

Var operator/(Var v1, Var v2)
{
  if(v1->length()==v2->length() && v1->width()==v2->width())
    return new DivVariable(v1,v2);
  else
    return v1*invertElements(v2);
}

Var operator==(Var v1, Var v2)
{ return isequal(v1,v2); }

Var operator!=(Var v1, Var v2)
{ return (1.0 - isequal(v1,v2) ); }

Var isdifferent(Var v1, Var v2)
{ return (1.0 - isequal(v1,v2) ); }


} // end of namespace PLearn

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