Mercurial > hg > camir-aes2014
view toolboxes/FullBNT-1.0.7/bnt/inference/static/@belprop_inf_engine/belprop_inf_engine.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 engine = belprop_inf_engine(bnet, varargin) % BELPROP_INF_ENGINE Make a loopy belief propagation inference engine % engine = belprop_inf_engine(bnet, ...) % % This is like pearl_inf_engine, except it uses potential objects, % instead of lambda/pi structs. Hence it is slower. % % The following optional arguments can be specified in the form of name/value pairs: % [default in brackets] % % protocol - 'tree' means send messages up then down the tree, % 'parallel' means use synchronous updates ['parallel'] % max_iter - max. num. iterations [ 2*num_nodes ] % momentum - weight assigned to old message in convex combination (useful for damping oscillations) [0] % tol - tolerance used to assess convergence [1e-3] % maximize - 1 means use max-product, 0 means use sum-product [0] % filename - name of file to write beliefs to after each iteration within enter_evidence [ [] ] % % e.g., engine = belprop_inf_engine(bnet, 'maximize', 1, 'max_iter', 10) % gdl = general distributive law engine.gdl = bnet_to_gdl(bnet); % set default params N = length(engine.gdl.G); engine.protocol = 'parallel'; engine.max_iter = 2*N; engine.momentum = 0; engine.tol = 1e-3; engine.maximize = 0; engine.filename = []; engine.fid = []; args = varargin; nargs = length(args); for i=1:2:nargs switch args{i}, case 'max_iter', engine.max_iter = args{i+1}; case 'momentum', engine.momentum = args{i+1}; case 'tol', engine.tol = args{i+1}; case 'protocol', engine.protocol = args{i+1}; case 'filename', engine.filename = args{i+1}; otherwise, error(['invalid argument name ' args{i}]); end end if strcmp(engine.protocol, 'tree') % Make a rooted tree, so there is a fixed message passing order. root = N; [engine.tree, engine.preorder, engine.postorder, height, cyclic] = mk_rooted_tree(engine.gdl.G, root); assert(~cyclic); end % store results computed by enter_evidence here engine.marginal_domains = cell(1, N); engine.niter = []; engine = class(engine, 'belprop_inf_engine', inf_engine(bnet)); %%%%%%%%% function gdl = bnet_to_gdl(bnet) gdl.G = mk_undirected(bnet.dag); N = length(bnet.dag); gdl.doms = cell(1,N); for i=1:N gdl.doms{i} = family(bnet.dag, i); end % Compute a bit vector representation of the set of domains % dom_bitv(i,j) = 1 iff variable j occurs in domain i gdl.dom_bitv = zeros(N, N); for i=1:N gdl.dom_bitv(i, gdl.doms{i}) = 1; end % compute the interesection of the domains on either side of each edge (separating set) gdl.sepset = cell(N, N); gdl.nbrs = cell(1,N); for i=1:N nbrs = neighbors(gdl.G, i); gdl.nbrs{i} = nbrs; for j = nbrs(:)' gdl.sepset{i,j} = myintersect(gdl.doms{i}, gdl.doms{j}); end end