jtree_unrolled_dbn_inf_engine.m

来自「Bayes网络工具箱」· M 代码 · 共 46 行

function engine = jtree_unrolled_dbn_inf_engine(bnet, T, onodes, fast, compiled)
% JTREE_UNROLLED_DBN_INF_ENGINE Unroll the DBN for T time-slices and apply jtree to the resulting static net
%
% engine = jtree_unrolled_dbn_inf_engine(bnet, T)
% Specifies that all sequences will have T time-slices.
% For variable length sequences, use jtree_dbn_inf_engine.
%
% engine = jtree_unrolled_dbn_inf_engine(bnet, T, onodes)
% 'onodes' specifies which nodes are observed nodes in every slice.
%
% engine = jtree_unrolled_dbn_inf_engine(bnet, T, onodes, fast)
% where 'fast' is a non-empty argument means use jtree_fast instead of jtree.
%
% engine = jtree_unrolled_dbn_inf_engine(bnet, T, onodes, fast, compiled)
% where 'compiled' is a non-empty argument means compile jtree_fast first.

if nargin < 3, onodes = []; end
if nargin < 4 | isempty(fast), fast = 0; else fast = 1; end
if nargin < 5 | isempty(compiled), compiled = 0; else compiled = 1; end
  
bnet2 = dbn_to_bnet(bnet, T);
ss = length(bnet.intra);
onodes = unroll_set(onodes, ss, T);

constrained_order = 0;
% If constrained_order = 1 we constrain ourselves to eliminate slice t before t+1.
% This prevents cliques containing nodes from far-apart time-slices.
if constrained_order
  stages = num2cell(unroll_set(1:ss, ss, T), 1);
else
  stages = { 1:length(bnet2.dag) };
end
clusters = [];
if fast
  jengine = jtree_fast_inf_engine(bnet2, onodes(:), clusters, compiled, stages);
else
  jengine = jtree_inf_engine(bnet2, onodes(:), clusters, stages);
end

engine.sub_engine = jengine;
% we don't inherit from jtree_inf_engine, because that would only store bnet2,
% and we would lose access to the DBN-specific fields like intra/inter

engine.nslices = T;
engine = class(engine, 'jtree_unrolled_dbn_inf_engine', inf_engine(bnet));