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replaced pow with bit shift operator, changed constructor to take p(x|parents) and created cpt inside the constructor.

release/4.3a0
Manohar Paluri 2009-12-07 03:25:25 +00:00
parent 28eb550781
commit 115d9a8adf
2 changed files with 15 additions and 11 deletions
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14
cpp/BinaryConditional.h
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@ -54,15 +54,19 @@ namespace gtsam {
BinaryConditional(const std::string& key, const std::string& parent, const std::vector<double>& cpt) : BinaryConditional(const std::string& key, const std::string& parent, const std::vector<double>& cpt) :
Conditional(key) { Conditional(key) {
parents_.push_back(parent); parents_.push_back(parent);
cpt_ = cpt; for( int i = 0 ; i < cpt.size() ; i++ )
cpt_.push_back(1-cpt[i]); // p(!x|parents)
cpt_.insert(cpt_.end(),cpt.begin(),cpt.end()); // p(x|parents)
} }
double probability( std::map<std::string,bool> config) { double probability( std::map<std::string,bool> config) {
int index = 0, count = 0; int index = 0, count = 1;
BOOST_FOREACH( std::string parent, parents_) BOOST_FOREACH( std::string parent, parents_){
index += pow(2,count++)*(int)(config[parent]); index += count*(int)(config[parent]);
count = count << 1;
}
if( config.find(key_)->second ) if( config.find(key_)->second )
index += pow(2,count); index += count;
return cpt_[index]; return cpt_[index];
} }

12
cpp/testBinaryBayesNet.cpp
View File

@ -31,7 +31,7 @@ using namespace gtsam;
/** A Bayes net made from binary conditional probability tables */ /** A Bayes net made from binary conditional probability tables */
typedef BayesNet<BinaryConditional> BinaryBayesNet; typedef BayesNet<BinaryConditional> BinaryBayesNet;
/* ************************************************************************* */ /************************************************************************** */
TEST( BinaryBayesNet, constructor ) TEST( BinaryBayesNet, constructor )
{ {
// small Bayes Net x <- y // small Bayes Net x <- y
@ -40,19 +40,19 @@ TEST( BinaryBayesNet, constructor )
// p(x|y=1) = 0.6 // p(x|y=1) = 0.6
map<string,bool> config; map<string,bool> config;
config["y"] = false; config["y"] = true;
config["x"] = false; config["x"] = true;
// unary conditional for y // unary conditional for y
boost::shared_ptr<BinaryConditional> py(new BinaryConditional("y",0.2)); boost::shared_ptr<BinaryConditional> py(new BinaryConditional("y",0.2));
py->print("py"); py->print("py");
DOUBLES_EQUAL(0.8,py->probability(config),0.01); DOUBLES_EQUAL(0.2,py->probability(config),0.01);
// single parent conditional for x // single parent conditional for x
vector<double> cpt; vector<double> cpt;
cpt += 0.7, 0.4, 0.3, 0.6 ; // array index corresponds to binary parent configuration cpt += 0.3, 0.6 ; // array index corresponds to binary parent configuration
boost::shared_ptr<BinaryConditional> px_y(new BinaryConditional("x","y",cpt)); boost::shared_ptr<BinaryConditional> px_y(new BinaryConditional("x","y",cpt));
px_y->print("px_y"); px_y->print("px_y");
DOUBLES_EQUAL(0.7,px_y->probability(config),0.01); DOUBLES_EQUAL(0.6,px_y->probability(config),0.01);
// push back conditionals in topological sort order (parents last) // push back conditionals in topological sort order (parents last)
BinaryBayesNet bbn; BinaryBayesNet bbn;