DuplicateScalarVariable.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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/* *******************************************************      
   * $Id: DuplicateScalarVariable.cc,v 1.6 2004/04/27 16:03:35 morinf Exp $
   * This file is part of the PLearn library.
   ******************************************************* */

#include "DuplicateScalarVariable.h"
#include "SumVariable.h"
//#include "Var_utils.h"

namespace PLearn {
using namespace std;


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

DuplicateScalarVariable::DuplicateScalarVariable(Variable* input, int thelength, int thewidth)
  : inherited(input, thelength, thewidth), length_(thelength), width_(thewidth)
{
    build_();
}

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

void
DuplicateScalarVariable::build_()
{
    if (input && !input->isScalar())
        PLERROR("In DuplicateScalarVariable input is not a scalar");
}

void
DuplicateScalarVariable::declareOptions(OptionList &ol)
{
    declareOption(ol, "length_", &DuplicateScalarVariable::length_, OptionBase::buildoption, "");
    declareOption(ol, "width_", &DuplicateScalarVariable::width_, OptionBase::buildoption, "");
    inherited::declareOptions(ol);
}

void DuplicateScalarVariable::recomputeSize(int& l, int& w) const
{ l=length_; w=width_; }


void DuplicateScalarVariable::fprop()
{
  real val = input->valuedata[0];
  for(int k=0; k<nelems(); k++)
    valuedata[k] = val;
}


void DuplicateScalarVariable::bprop()
{
  real& inputgrad = input->gradientdata[0];
  for(int k=0; k<nelems(); k++)
    inputgrad += gradientdata[k];
}


void DuplicateScalarVariable::symbolicBprop()
{
  input->accg(sum(g));
}



} // end of namespace PLearn

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