Mercurial > hg > camir-aes2014
view toolboxes/FullBNT-1.0.7/bnt/inference/dynamic/@frontier_inf_engine/enter_soft_evidence.m @ 0:e9a9cd732c1e tip
first hg version after svn
author | wolffd |
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date | Tue, 10 Feb 2015 15:05:51 +0000 |
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function [fwdback, loglik, fwd_frontier, back_frontier] = enter_soft_evidence(engine, CPD, onodes, pot_type, filter) % ENTER_SOFT_EVIDENCE Add soft evidence to network (frontier) % [fwdback, loglik] = enter_soft_evidence(engine, CPDpot, onodes, filter) if nargin < 3, filter = 0; end [ss T] = size(CPD); bnet = bnet_from_engine(engine); ns = repmat(bnet.node_sizes_slice(:), 1, T); cnodes = unroll_set(bnet.cnodes(:), ss, T); % FORWARDS fwd = cell(ss,T); ll = zeros(1,T); S = 2*ss; % num. intermediate frontiers to get from t to t+1 frontier = cell(S,T); % Start with empty frontier, and add each node in slice 1 init = mk_initial_pot(pot_type, [], ns, cnodes, onodes); t = 1; s = 1; j = 1; frontier{s,t} = update(init, j, 1, CPD{j}, engine.fdom1{s}, pot_type, ns, cnodes, onodes); fwd{j} = frontier{s,t}; for s=2:ss j = s; % add node j at step s frontier{s,t} = update(frontier{s-1,t}, j, 1, CPD{j}, engine.fdom1{s}, pot_type, ns, cnodes, onodes); fwd{j} = frontier{s,t}; end frontier{S,t} = frontier{ss,t}; [frontier{S,t}, ll(1)] = normalize_pot(frontier{S,t}); % Now move frontier from slice to slice OPS = engine.ops; add = OPS>0; nodes = [zeros(S,1) unroll_set(abs(OPS(:)), ss, T-1)]; for t=2:T offset = (t-2)*ss; for s=1:S if s==1 prev_ndx = (t-2)*S + S; % S,t-1 else prev_ndx = (t-1)*S + s-1; % s-1,t end j = nodes(s,t); frontier{s,t} = update(frontier{prev_ndx}, j, add(s), CPD{j}, engine.fdom{s}+offset, pot_type, ns, cnodes, onodes); if add(s) fwd{j} = frontier{s,t}; end end [frontier{S,t}, ll(t)] = normalize_pot(frontier{S,t}); end loglik = sum(ll); fwd_frontier = frontier; if filter fwdback = fwd; return; end % BACKWARDS back = cell(ss,T); add = ~add; % forwards add = backwards remove frontier = cell(S,T+1); t = T; dom = (1:ss) + (t-1)*ss; frontier{1,T+1} = mk_initial_pot(pot_type, dom, ns, cnodes, onodes); % all 1s for last slice for t=T:-1:2 offset = (t-2)*ss; for s=S:-1:1 % reverse order if s==S prev_ndx = t*S + 1; % 1,t+1 else prev_ndx = (t-1)*S + (s+1); % s+1,t end j = nodes(s,t); if ~add(s) back{j} = frontier{prev_ndx}; % save frontier before removing end frontier{s,t} = rev_update(frontier{prev_ndx}, t, s, j, add(s), CPD{j}, engine.fdom{s}+offset, pot_type, ns, cnodes, onodes); end frontier{1,t} = normalize_pot(frontier{1,t}); end % Remove each node in first slice until left with empty set t = 1; frontier{ss+1,t} = frontier{1,2}; add = 0; for s=ss:-1:1 j = s; % remove node j at step s back{j} = frontier{s+1,t}; frontier{s,t} = rev_update(frontier{s+1,t}, t, s, j, add, CPD{j}, 1:s, pot_type, ns, cnodes, onodes); end % COMBINE for t=1:T for i=1:ss %fwd{i,t} = multiply_by_pot(fwd{i,t}, back{i,t}); %fwdback{i,t} = normalize_pot(fwd{i,t}); fwdback{i,t} = normalize_pot(multiply_pots(fwd{i,t}, back{i,t})); end end back_frontier = frontier; %%%%%%%%%% function new_frontier = update(old_frontier, j, add, CPD, newdom, pot_type, ns, cnodes, onodes) if add new_frontier = mk_initial_pot(pot_type, newdom, ns, cnodes, onodes); new_frontier = multiply_by_pot(new_frontier, old_frontier); new_frontier = multiply_by_pot(new_frontier, CPD); else new_frontier = marginalize_pot(old_frontier, mysetdiff(domain_pot(old_frontier), j)); end %%%%%% function new_frontier = rev_update(old_frontier, t, s, j, add, CPD, junk, pot_type, ns, cnodes, onodes) olddom = domain_pot(old_frontier); assert(isequal(junk, olddom)); if add % add: extend domain to include j by multiplying by 1 newdom = myunion(olddom, j); new_frontier = mk_initial_pot(pot_type, newdom, ns, cnodes, onodes); new_frontier = multiply_by_pot(new_frontier, old_frontier); %fprintf('t=%d, s=%d, add %d to %s to make %s\n', t, s, j, num2str(olddom), num2str(newdom)); else % remove: multiply in CPT and then marginalize out j % parents of j are guaranteed to be in old_frontier, else couldn't have added j on fwds pass old_frontier = multiply_by_pot(old_frontier, CPD); newdom = mysetdiff(olddom, j); new_frontier = marginalize_pot(old_frontier, newdom); %newdom2 = domain_pot(new_frontier); %fprintf('t=%d, s=%d, rem %d from %s to make %s\n', t, s, j, num2str(olddom), num2str(newdom2)); end