141 lines
4.8 KiB
C++
141 lines
4.8 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 Ordering.cpp
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* @author Richard Roberts
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* @date Sep 2, 2010
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*/
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#pragma once
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#include <vector>
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#include <limits>
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#include <gtsam/inference/Ordering.h>
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#include <gtsam/3rdparty/CCOLAMD/Include/ccolamd.h>
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using namespace std;
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namespace gtsam {
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/* ************************************************************************* */
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FastMap<Key, size_t> Ordering::invert() const
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{
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FastMap<Key, size_t> inverted;
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for(size_t pos = 0; pos < this->size(); ++pos)
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inverted.insert(make_pair((*this)[pos], pos));
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return inverted;
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}
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/* ************************************************************************* */
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Ordering Ordering::COLAMD(const VariableIndex& variableIndex)
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{
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// Call constrained version with all groups set to zero
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return Ordering::COLAMDConstrained(variableIndex, vector<int>(variableIndex.size(), 0));
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}
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/* ************************************************************************* */
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Ordering Ordering::COLAMDConstrained(
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const VariableIndex& variableIndex, std::vector<int>& cmember)
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{
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gttic(Ordering_COLAMDConstrained);
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gttic(Prepare);
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size_t nEntries = variableIndex.nEntries(), nFactors = variableIndex.nFactors(), nVars = variableIndex.size();
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// Convert to compressed column major format colamd wants it in (== MATLAB format!)
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size_t Alen = ccolamd_recommended((int)nEntries, (int)nFactors, (int)nVars); /* colamd arg 3: size of the array A */
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vector<int> A = vector<int>(Alen); /* colamd arg 4: row indices of A, of size Alen */
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vector<int> p = vector<int>(nVars + 1); /* colamd arg 5: column pointers of A, of size n_col+1 */
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// Fill in input data for COLAMD
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p[0] = 0;
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int count = 0;
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vector<Key> keys(nVars); // Array to store the keys in the order we add them so we can retrieve them in permuted order
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size_t index = 0;
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BOOST_FOREACH(const VariableIndex::value_type key_factors, variableIndex) {
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// Arrange factor indices into COLAMD format
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const VariableIndex::Factors& column = key_factors.second;
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size_t lastFactorId = numeric_limits<size_t>::max();
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BOOST_FOREACH(size_t factorIndex, column) {
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if(lastFactorId != numeric_limits<size_t>::max())
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assert(factorIndex > lastFactorId);
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A[count++] = (int)factorIndex; // copy sparse column
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}
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p[index+1] = count; // column j (base 1) goes from A[j-1] to A[j]-1
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// Store key in array and increment index
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keys[index] = key_factors.first;
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++ index;
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}
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assert((size_t)count == variableIndex.nEntries());
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//double* knobs = NULL; /* colamd arg 6: parameters (uses defaults if NULL) */
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double knobs[CCOLAMD_KNOBS];
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ccolamd_set_defaults(knobs);
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knobs[CCOLAMD_DENSE_ROW]=-1;
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knobs[CCOLAMD_DENSE_COL]=-1;
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int stats[CCOLAMD_STATS]; /* colamd arg 7: colamd output statistics and error codes */
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gttoc(Prepare);
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// call colamd, result will be in p
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/* returns (1) if successful, (0) otherwise*/
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if(nVars > 0) {
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gttic(ccolamd);
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int rv = ccolamd((int)nFactors, (int)nVars, (int)Alen, &A[0], &p[0], knobs, stats, &cmember[0]);
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if(rv != 1)
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throw runtime_error((boost::format("ccolamd failed with return value %1%")%rv).str());
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}
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// ccolamd_report(stats);
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gttic(Fill_Ordering);
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// Convert elimination ordering in p to an ordering
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Ordering result;
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result.resize(nVars);
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for(size_t j = 0; j < nVars; ++j)
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result[j] = keys[p[j]];
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gttoc(Fill_Ordering);
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return result;
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}
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/* ************************************************************************* */
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Ordering Ordering::COLAMDConstrainedLast(
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const VariableIndex& variableIndex, const std::vector<Key>& constrainLast, bool forceOrder)
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{
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gttic(Ordering_COLAMDConstrainedLast);
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size_t n = variableIndex.size();
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std::vector<int> cmember(n, 0);
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// Build a mapping to look up sorted Key indices by Key
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FastMap<Key, size_t> keyIndices;
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size_t j = 0;
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BOOST_FOREACH(const VariableIndex::value_type key_factors, variableIndex)
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keyIndices.insert(keyIndices.end(), make_pair(key_factors.first, j++));
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// If at least some variables are not constrained to be last, constrain the
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// ones that should be constrained.
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int group = (constrainLast.size() != n ? 1 : 0);
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BOOST_FOREACH(Key key, constrainLast) {
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cmember[keyIndices.at(key)] = group;
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if(forceOrder)
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++ group;
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}
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return Ordering::COLAMDConstrained(variableIndex, cmember);
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}
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}
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