void variable_elimination(std::list<annotated<Arg, F> >& factors,
const domain<Arg>& retain,
const commutative_semiring<Arg, F>& csr,
Strategy strategy = Strategy()) {
// construct the Markov graph for the input factors
undirected_graph<Arg> graph;
for (const annotated<Arg, F>& factor : factors) {
graph.make_clique(factor.domain);
}
// eliminate variables
eliminate(graph, [&](Arg arg) {
if (!retain.count(arg)) {
// Combine all factors that have this variable as an argument
annotated<Arg, F> combination = csr.combine_init();
for (auto it = factors.begin(); it != factors.end();) {
if (it->domain.count(arg)) {
csr.combine_in(combination, *it);
factors.erase(it++);
} else {
++it;
}
}
factors.push_back(csr.eliminate(combination, arg));
}
}, strategy);
}
typename Range::value_type
combine_all(const Range& factors,
const commutative_semiring<typename Range::value_type>& csr) {
concept_assert((InputRange<Range>));
typedef typename Range::value_type factor_type;
factor_type result = csr.combine_init();
foreach(const factor_type& f, factors) {
csr.combine_in(result, f);
}