Mercurial > hg > camir-aes2014
view toolboxes/FullBNT-1.0.7/bnt/inference/static/@var_elim_inf_engine/marginal_nodes.m @ 0:e9a9cd732c1e tip
first hg version after svn
author | wolffd |
---|---|
date | Tue, 10 Feb 2015 15:05:51 +0000 |
parents | |
children |
line wrap: on
line source
function [marginal, loglik] = marginal_nodes(engine, query, add_ev) % MARGINAL_NODES Compute the marginal on the specified query nodes (var_elim) % [marginal, loglik] = marginal_nodes(engine, query) if nargin < 3, add_ev = 0; end assert(length(query)>=1); evidence = engine.evidence; bnet = bnet_from_engine(engine); ns = bnet.node_sizes; n = length(bnet.dag); onodes = find(~isemptycell(evidence)); hnodes = find(isemptycell(evidence)); pot_type = determine_pot_type(bnet, onodes); % Fold the evidence into the CPTs - this could be done in 'enter_evidence' CPT = cell(1,n); for i=1:n fam = family(bnet.dag, i); CPT{i} = convert_to_pot(bnet.CPD{bnet.equiv_class(i)}, pot_type, fam(:), evidence); end sum_over = mysetdiff(1:n, query); order = [query sum_over]; % no attempt to optimize this % Initialize the buckets with the product of the CPTs assigned to them B = cell(1,n+1); for b=1:n+1 B{b} = mk_initial_pot(pot_type, [], [], [], []); end for i=1:n b = bucket_num(domain_pot(CPT{i}), order); B{b} = multiply_pots(B{b}, CPT{i}); end % Do the marginalization sum_over = sum_over(length(sum_over):-1:1); % reverse for i=sum_over(:)' % summing over variable i which occurs in bucket j j = bucket_num(i, order); rest = mysetdiff(domain_pot(B{j}), i); % minka if ~isempty(rest) temp = marginalize_pot(B{j}, rest); b = bucket_num(domain_pot(temp), order); %fprintf('summing over bucket %d (var %d), putting result into bucket %d\n', j, i, b); B{b} = multiply_pots(B{b}, temp); end end % Combine all the remaining buckets into one result = B{1}; for i=2:length(query) if ~isempty(domain_pot(B{i})) result = multiply_pots(result, B{i}); end end [result, loglik] = normalize_pot(result); marginal = pot_to_marginal(result); % minka: from jtree_inf_engine if add_ev bnet = bnet_from_engine(engine); %marginal = add_ev_to_dmarginal(marginal, engine.evidence, bnet.node_sizes); marginal = add_evidence_to_gmarginal(marginal, engine.evidence, bnet.node_sizes, bnet.cnodes); end %%%%%%%%% function b = bucket_num(domain, order) b = max(find_equiv_posns(domain, order));