129 lines
3.7 KiB
C++
129 lines
3.7 KiB
C++
/* ----------------------------------------------------------------------------
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* GTSAM Copyright 2010, Georgia Tech Research Corporation,
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* Atlanta, Georgia 30332-0415
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* All Rights Reserved
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* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
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* See LICENSE for the license information
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* -------------------------------------------------------------------------- */
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/**
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* @file Permutation.cpp
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* @brief
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* @author Richard Roberts
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* @created Oct 9, 2010
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*/
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#include <gtsam/inference/Permutation.h>
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#include <iostream>
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#include <boost/foreach.hpp>
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using namespace std;
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namespace gtsam {
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/* ************************************************************************* */
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Permutation Permutation::Identity(Index nVars) {
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Permutation ret(nVars);
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for(Index i=0; i<nVars; ++i)
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ret[i] = i;
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return ret;
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}
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/* ************************************************************************* */
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Permutation Permutation::PullToFront(const vector<Index>& toFront, size_t size) {
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Permutation ret(size);
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// Mask of which variables have been pulled, used to reorder
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vector<bool> pulled(size, false);
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// Put the pulled variables at the front of the permutation and set up the
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// pulled flags.
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for(Index j=0; j<toFront.size(); ++j) {
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ret[j] = toFront[j];
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pulled[toFront[j]] = true;
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}
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// Fill in the rest of the variables
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Index nextVar = toFront.size();
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for(Index j=0; j<size; ++j)
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if(!pulled[j])
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ret[nextVar++] = j;
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assert(nextVar == size);
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return ret;
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}
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/* ************************************************************************* */
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Permutation Permutation::PushToBack(const std::vector<Index>& toBack, size_t size) {
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Permutation ret(size);
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// Mask of which variables have been pushed, used to reorder
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vector<bool> pushed(size, false);
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// Put the pushed variables at the back of the permutation and set up the
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// pushed flags;
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Index nextVar = size - toBack.size();
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for(Index j=0; j<toBack.size(); ++j) {
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ret[nextVar++] = toBack[j];
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pushed[toBack[j]] = true;
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}
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assert(nextVar == size);
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// Fill in the rest of the variables
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nextVar = 0;
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for(Index j=0; j<size; ++j)
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if(!pushed[j])
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ret[nextVar++] = j;
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assert(nextVar == size - toBack.size());
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return ret;
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}
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/* ************************************************************************* */
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Permutation::shared_ptr Permutation::permute(const Permutation& permutation) const {
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const size_t nVars = permutation.size();
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Permutation::shared_ptr result(new Permutation(nVars));
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for(size_t j=0; j<nVars; ++j) {
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assert(permutation[j] < rangeIndices_.size());
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(*result)[j] = operator[](permutation[j]);
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}
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return result;
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}
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/* ************************************************************************* */
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Permutation::shared_ptr Permutation::partialPermutation(
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const Permutation& selector, const Permutation& partialPermutation) const {
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assert(selector.size() == partialPermutation.size());
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Permutation::shared_ptr result(new Permutation(*this));
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for(Index subsetPos=0; subsetPos<selector.size(); ++subsetPos)
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(*result)[selector[subsetPos]] = (*this)[selector[partialPermutation[subsetPos]]];
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return result;
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}
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/* ************************************************************************* */
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Permutation::shared_ptr Permutation::inverse() const {
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Permutation::shared_ptr result(new Permutation(this->size()));
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for(Index i=0; i<this->size(); ++i) {
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assert((*this)[i] < this->size());
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(*result)[(*this)[i]] = i;
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}
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return result;
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}
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/* ************************************************************************* */
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void Permutation::print(const std::string& str) const {
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std::cout << str;
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BOOST_FOREACH(Index s, rangeIndices_) { std::cout << s << " "; }
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std::cout << std::endl;
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}
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}
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