SubMatTransposeVariable.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: SubMatTransposeVariable.cc,v 1.7 2004/05/26 20:14:38 tihocan Exp $
   * This file is part of the PLearn library.
   ******************************************************* */

#include "ExtendedVariable.h"
#include "SubMatTransposeVariable.h"
//#include "Var_utils.h"

namespace PLearn {
using namespace std;


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

SubMatTransposeVariable::SubMatTransposeVariable(Variable* v, int i, int j, int the_length, int the_width)
: inherited(v, the_width, the_length),
  startk(i*v->length()+j),
  length_(the_length),
  width_(the_width),
  i_(i),
  j_(j)
{
    build_();
}

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

void SubMatTransposeVariable::build_()
{
    if (input) {
        // input is v from constructor
        if (i_ < 0 || i_ + length_ > input->length() || j_ < 0 || j_ + width_ > input->width())
            PLERROR("In SubMatTransposeVariable: requested sub-matrix is out of matrix bounds");
        startk = i_ * input->length() + j_;
    }
}

void
SubMatTransposeVariable::declareOptions(OptionList &ol)
{
    declareOption(ol, "length_", &SubMatTransposeVariable::length_, OptionBase::buildoption, "");
    declareOption(ol, "width_", &SubMatTransposeVariable::width_, OptionBase::buildoption, "");
    declareOption(ol, "startk", &SubMatTransposeVariable::startk, OptionBase::buildoption, "");
    declareOption(ol, "i_", &SubMatTransposeVariable::i_, OptionBase::buildoption, "");
    declareOption(ol, "j_", &SubMatTransposeVariable::j_, OptionBase::buildoption, "");
    inherited::declareOptions(ol);
}

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

void SubMatTransposeVariable::fprop()
{
  if(input->length()==1 || input->width()==1) // optimized version for this special case...
    {
      real* inputdata = input->valuedata+startk;
      for(int k=0; k<nelems(); k++)
        valuedata[k] = inputdata[k];
    }
  else // general case
    {
      real* inputrowdata = input->valuedata+startk;
      int thiskcolstart = 0; // element index of start of column in this var
      for(int i=0; i<width(); i++) // the width() of this var is the length() of the submat
        {
          int thisk = thiskcolstart++;
          for(int j=0; j<length(); j++, thisk+=width()) // the length() of this var is the width() of the submat
            valuedata[thisk] = inputrowdata[j];
          inputrowdata += input->width();
        }
    }
}


void SubMatTransposeVariable::bprop()
{
  if(input->length()==1 || input->width()==1) // optimized version for this special case...
    {
      real* inputdata = input->gradientdata+startk;
      for(int k=0; k<nelems(); k++)
        inputdata[k] += gradientdata[k];
    }
  else // general case
    {
      real* inputrowdata = input->gradientdata+startk;
      int thiskcolstart = 0; // element index of start of column in this var
      for(int i=0; i<width(); i++) // the width() of this var is the length() of the submat
        {
          int thisk = thiskcolstart++;
          for(int j=0; j<length(); j++, thisk+=width()) // the length() of this var is the width() of the submat
            inputrowdata[j] += gradientdata[thisk];
          inputrowdata += input->width();
        }
    }
}


void SubMatTransposeVariable::symbolicBprop()
{
  int i = startk/input->width();
  int j = startk%input->width();
  int topextent = i;
  int bottomextent = input->length()-(i+width()); // the width() of this var is the length() of the submat
  int leftextent = j;
  int rightextent = input->width()-(j+length()); // the length() of this var is the width() of the submat
  input->accg(extend(transpose(g),topextent,bottomextent,leftextent,rightextent));
}


void SubMatTransposeVariable::rfprop()
{
  if (rValue.length()==0) resizeRValue();
  if(input->length()==1 || input->width()==1) // optimized version for this special case...
    {
      real* inputdata = input->rvaluedata+startk;
      for(int k=0; k<nelems(); k++)
        rvaluedata[k] = inputdata[k];
    }
  else // general case
    {
      real* inputrowdata = input->rvaluedata+startk;
      int thiskcolstart = 0; // element index of start of column in this var
      for(int i=0; i<width(); i++) // the width() of this var is the length() of the submat
        {
          int thisk = thiskcolstart++;
          for(int j=0; j<length(); j++, thisk+=width()) // the length() of this var is the width() of the submat
            rvaluedata[thisk] = inputrowdata[j];
          inputrowdata += input->width();
        }
    }
}



} // end of namespace PLearn

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