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use TableFactor instead of DecisionTreeFactor in discrete elimination

release/4.3a0
Varun Agrawal 2024-12-27 14:29:16 -05:00
parent 02d461e359
commit 34fba6823a
2 changed files with 31 additions and 16 deletions
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44
gtsam/discrete/DiscreteFactorGraph.cpp
View File

@ -64,10 +64,18 @@ namespace gtsam {
}
/* ************************************************************************ */
DecisionTreeFactor DiscreteFactorGraph::product() const {
DecisionTreeFactor result;
TableFactor DiscreteFactorGraph::product() const {
TableFactor result;
for (const sharedFactor& factor : *this) {
if (factor) result = (*factor) * result;
if (factor) {
if (auto f = std::dynamic_pointer_cast<TableFactor>(factor)) {
result = result * (*f);
}
else if (auto dtf =
std::dynamic_pointer_cast<DecisionTreeFactor>(factor)) {
result = TableFactor(result * (*dtf));
}
}
}
return result;
}
@ -116,15 +124,14 @@ namespace gtsam {
* product to prevent underflow.
*
* @param factors The factors to multiply as a DiscreteFactorGraph.
* @return DecisionTreeFactor
* @return TableFactor
*/
static DecisionTreeFactor ProductAndNormalize(
const DiscreteFactorGraph& factors) {
static TableFactor ProductAndNormalize(const DiscreteFactorGraph& factors) {
// PRODUCT: multiply all factors
#if GTSAM_HYBRID_TIMING
gttic_(DiscreteProduct);
#endif
DecisionTreeFactor product = factors.product();
TableFactor product = factors.product();
#if GTSAM_HYBRID_TIMING
gttoc_(DiscreteProduct);
#endif
@ -149,11 +156,11 @@ namespace gtsam {
std::pair<DiscreteConditional::shared_ptr, DiscreteFactor::shared_ptr> //
EliminateForMPE(const DiscreteFactorGraph& factors,
const Ordering& frontalKeys) {
DecisionTreeFactor product = ProductAndNormalize(factors);
TableFactor product = ProductAndNormalize(factors);
// max out frontals, this is the factor on the separator
gttic(max);
DecisionTreeFactor::shared_ptr max = product.max(frontalKeys);
TableFactor::shared_ptr max = product.max(frontalKeys);
gttoc(max);
// Ordering keys for the conditional so that frontalKeys are really in front
@ -166,8 +173,8 @@ namespace gtsam {
// Make lookup with product
gttic(lookup);
size_t nrFrontals = frontalKeys.size();
auto lookup =
std::make_shared<DiscreteLookupTable>(nrFrontals, orderedKeys, product);
auto lookup = std::make_shared<DiscreteLookupTable>(
nrFrontals, orderedKeys, product.toDecisionTreeFactor());
gttoc(lookup);
return {std::dynamic_pointer_cast<DiscreteConditional>(lookup), max};
@ -227,13 +234,13 @@ namespace gtsam {
std::pair<DiscreteConditional::shared_ptr, DiscreteFactor::shared_ptr> //
EliminateDiscrete(const DiscreteFactorGraph& factors,
const Ordering& frontalKeys) {
DecisionTreeFactor product = ProductAndNormalize(factors);
TableFactor product = ProductAndNormalize(factors);
// sum out frontals, this is the factor on the separator
#if GTSAM_HYBRID_TIMING
gttic_(EliminateDiscreteSum);
#endif
DecisionTreeFactor::shared_ptr sum = product.sum(frontalKeys);
TableFactor::shared_ptr sum = product.sum(frontalKeys);
#if GTSAM_HYBRID_TIMING
gttoc_(EliminateDiscreteSum);
#endif
@ -246,11 +253,18 @@ namespace gtsam {
sum->keys().end());
// now divide product/sum to get conditional
#if GTSAM_HYBRID_TIMING
gttic_(EliminateDiscreteDivide);
#endif
auto c = product / (*sum);
#if GTSAM_HYBRID_TIMING
gttoc_(EliminateDiscreteDivide);
#endif
#if GTSAM_HYBRID_TIMING
gttic_(EliminateDiscreteToDiscreteConditional);
#endif
auto conditional =
std::make_shared<DiscreteConditional>(product, *sum, orderedKeys);
auto conditional = std::make_shared<DiscreteConditional>(
orderedKeys.size(), c.toDecisionTreeFactor());
#if GTSAM_HYBRID_TIMING
gttoc_(EliminateDiscreteToDiscreteConditional);
#endif

3
gtsam/discrete/DiscreteFactorGraph.h
View File

@ -25,6 +25,7 @@
#include <gtsam/inference/FactorGraph.h>
#include <gtsam/inference/Ordering.h>
#include <gtsam/base/FastSet.h>
#include <gtsam/discrete/TableFactor.h>
#include <string>
#include <utility>
@ -147,7 +148,7 @@ class GTSAM_EXPORT DiscreteFactorGraph
DiscreteKeys discreteKeys() const;
/** return product of all factors as a single factor */
DecisionTreeFactor product() const;
TableFactor product() const;
/**
* Evaluates the factor graph given values, returns the joint probability of