12345qiupeng
/
gtsam
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Optimized version of symbolic elimination

release/4.3a0
Richard Roberts 2011-02-07 16:39:37 +00:00
parent 5abe56aaab
commit 06db4ac770
2 changed files with 67 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
gtsam/inference/EliminationTree-inl.h
View File

@ -11,9 +11,12 @@
#include <gtsam/inference/EliminationTree.h>
#include <gtsam/inference/VariableSlots.h>
#include <gtsam/inference/FactorGraph-inl.h>
#include <gtsam/inference/IndexFactor.h>
#include <gtsam/inference/IndexConditional.h>
#include <boost/foreach.hpp>
#include <boost/lambda/lambda.hpp>
#include <boost/static_assert.hpp>
#include <iostream>
#include <set>
#include <vector>
@ -31,8 +34,6 @@ EliminationTree<FACTOR>::eliminate_(Conditionals& conditionals) const {
if(debug) cout << "ETree: eliminating " << this->key_ << endl;
FastSet<Index> separator;
// Create the list of factors to be eliminated, initially empty, and reserve space
FactorGraph<FACTOR> factors;
factors.reserve(this->factors_.size() + this->subTrees_.size());
@ -56,6 +57,39 @@ EliminationTree<FACTOR>::eliminate_(Conditionals& conditionals) const {
return eliminated.second;
}
/* ************************************************************************* */
// This is the explicit specialization for symbolic factors, i.e. IndexFactor
template<> inline FastSet<Index> EliminationTree<IndexFactor>::eliminateSymbolic_(Conditionals& conditionals) const {
static const bool debug = false;
if(debug) cout << "ETree: eliminating " << this->key_ << endl;
FastSet<Index> variables;
BOOST_FOREACH(const sharedFactor& factor, factors_) {
variables.insert(factor->begin(), factor->end());
}
BOOST_FOREACH(const shared_ptr& child, subTrees_) {
sharedFactor factor(child->eliminate_(conditionals));
variables.insert(factor->begin(), factor->end());
}
conditionals[this->key_] = IndexConditional::FromRange(variables.begin(), variables.end(), 1);
variables.erase(variables.begin());
if(debug) cout << "Eliminated " << this->key_ << " to get:\n";
if(debug) conditionals[this->key_]->print("Conditional: ");
return variables;
}
/* ************************************************************************* */
// This non-specialized version cannot be called.
template<class FACTOR> FastSet<Index>
EliminationTree<FACTOR>::eliminateSymbolic_(Conditionals& conditionals) const {
throw invalid_argument("symbolic eliminate should never be called from a non-IndexFactor EliminationTree");
return FastSet<Index>();
}
/* ************************************************************************* */
template<class FACTOR>
vector<Index> EliminationTree<FACTOR>::ComputeParents(const VariableIndex& structure) {
@ -204,4 +238,28 @@ EliminationTree<FACTOR>::eliminate() const {
return bayesNet;
}
/* ************************************************************************* */
// Specialization for symbolic elimination that calls the optimized eliminateSymbolic_
template<>
inline typename EliminationTree<IndexFactor>::BayesNet::shared_ptr
EliminationTree<IndexFactor>::eliminate() const {
// call recursive routine
tic(1, "ET recursive eliminate");
Conditionals conditionals(this->key_ + 1);
(void)eliminateSymbolic_(conditionals);
toc(1, "ET recursive eliminate");
// Add conditionals to BayesNet
tic(2, "assemble BayesNet");
typename BayesNet::shared_ptr bayesNet(new BayesNet);
BOOST_FOREACH(const typename BayesNet::sharedConditional& conditional, conditionals) {
if(conditional)
bayesNet->push_back(conditional);
}
toc(2, "assemble BayesNet");
return bayesNet;
}
}

7
gtsam/inference/EliminationTree.h
View File

@ -11,6 +11,7 @@
#include <utility>
#include <gtsam/base/FastList.h>
#include <gtsam/base/FastSet.h>
#include <gtsam/inference/VariableIndex.h>
#include <gtsam/inference/BayesNet.h>
#include <gtsam/inference/FactorGraph.h>
@ -62,6 +63,12 @@ private:
*/
sharedFactor eliminate_(Conditionals& conditionals) const;
/**
* Special optimized eliminate for symbolic factors. Will not compile if
* called in a non-IndexFactor EliminationTree.
*/
FastSet<Index> eliminateSymbolic_(Conditionals& conditionals) const;
// Allow access to constructor and add methods for testing purposes
friend class ::EliminationTreeTester;