BootstrapSplitter.cc

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// -*- C++ -*-

// BootstrapSplitter.cc
//
// Copyright (C) 2003 Olivier Delalleau 
// 
// 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.
// 
// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
// NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// 
// 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: BootstrapSplitter.cc,v 1.3 2004/04/05 22:47:08 morinf Exp $ 
   ******************************************************* */

#include "BootstrapSplitter.h"
#include "BootstrapVMatrix.h"

namespace PLearn {
using namespace std;

BootstrapSplitter::BootstrapSplitter() 
  :Splitter(),
  frac(0.6667),
  n_splits(0)
  /* ### Initialise all fields to their default value */
{
}

PLEARN_IMPLEMENT_OBJECT(BootstrapSplitter, 
    "A splitter whose splits are bootstrap samples of the original dataset", 
    "BootstrapSplitter implements a ...");

void BootstrapSplitter::declareOptions(OptionList& ol)
{
  // ### Declare all of this object's options here
  // ### For the "flags" of each option, you should typically specify  
  // ### one of OptionBase::buildoption, OptionBase::learntoption or 
  // ### OptionBase::tuningoption. Another possible flag to be combined with
  // ### is OptionBase::nosave

  declareOption(ol, "n_splits", &BootstrapSplitter::n_splits, OptionBase::buildoption,
                 "the number of splits wanted");

  declareOption(ol, "frac", &BootstrapSplitter::frac, OptionBase::buildoption,
                 "the fraction of elements to take in each bootstrap");

  // Now call the parent class' declareOptions
  inherited::declareOptions(ol);
}

void BootstrapSplitter::build_()
{
  // ### This method should do the real building of the object,
  // ### according to set 'options', in *any* situation. 
  // ### Typical situations include:
  // ###  - Initial building of an object from a few user-specified options
  // ###  - Building of a "reloaded" object: i.e. from the complete set of all serialised options.
  // ###  - Updating or "re-building" of an object after a few "tuning" options have been modified.
  // ### You should assume that the parent class' build_() has already been called.
  if (dataset) {
    bootstrapped_sets.resize(0,0); // First clear the current sets.
    bootstrapped_sets.resize(n_splits,1);
    for (int i = 0; i < n_splits; i++) {
      // Construct a new bootstrap sample from the dataset.
      bootstrapped_sets(i,0) = new BootstrapVMatrix(dataset,frac);
    }
  } else {
    bootstrapped_sets.resize(0,0);
  }
}

// ### Nothing to add here, simply calls build_
void BootstrapSplitter::build()
{
  inherited::build();
  build_();
}

void BootstrapSplitter::makeDeepCopyFromShallowCopy(map<const void*, void*>& copies)
{
  Splitter::makeDeepCopyFromShallowCopy(copies);

  // ### Call deepCopyField on all "pointer-like" fields 
  // ### that you wish to be deepCopied rather than 
  // ### shallow-copied.
  // ### ex:
  // deepCopyField(trainvec, copies);

  // ### Remove this line when you have fully implemented this method.
  PLERROR("BootstrapSplitter::makeDeepCopyFromShallowCopy not fully (correctly) implemented yet!");
}

int BootstrapSplitter::nsplits() const
{
  // ### Return the number of available splits
  return n_splits;
}

int BootstrapSplitter::nSetsPerSplit() const
{
  // ### Return the number of sets per split
  return 1;
}

TVec<VMat> BootstrapSplitter::getSplit(int k)
{
  // ### Build and return the kth split 
  if (k >= n_splits) {
    PLERROR("BootstrapSplitter::getSplit: k is too high");
  } else if (k >= bootstrapped_sets.length()) {
    PLERROR("BootstrapSplitter::getSplit: you asked for a split but they're not ready yet");
  }
  return bootstrapped_sets(k);
}

// setDataSet //
void BootstrapSplitter::setDataSet(VMat the_dataset) {
  inherited::setDataSet(the_dataset);
  build(); // necessary to recompute the bootstrap samples.
}

} // end of namespace PLearn

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