enter_evidence.m

来自「Bayes网络工具箱」· M 代码 · 共 36 行

function [engine, loglik] = enter_evidence(engine, evidence, filter)
% ENTER_EVIDENCE Add the specified evidence to the network (bk)
% [engine, loglik] = enter_evidence(engine, evidence, filter)
%
% evidence{i,t} = [] if if X(i,t) is hidden, and otherwise contains its observed value (scalar or column vector)
% If filter = 1, we do filtering, else smoothing. (Default: filter = 0.)

if nargin < 3, filter = 0; end

[ss T] = size(evidence);
observed = ~isemptycell(evidence);
bnet = bnet_from_engine(engine);
pot_type = determine_pot_type(find(observed(:,1)), bnet.cnodes_slice, bnet.intra);
% we assume we can use the same pot_type in all slices

% Convert CPDs of instantiated nodes to potential form
CPDpot = cell(ss,T);      
t = 1;
for n=1:ss
  fam = family(bnet.dag, n);
  e = bnet.equiv_class(n, 1);
  CPDpot{n,t} = CPD_to_pot(pot_type, bnet.CPD{e}, fam, bnet.node_sizes(:), bnet.cnodes(:), evidence(:,1));
end
for t=2:T
  for n=1:ss
    fam = family(bnet.dag, n, 2);
    e = bnet.equiv_class(n, 2);
    CPDpot{n,t} = CPD_to_pot(pot_type, bnet.CPD{e}, fam, bnet.node_sizes(:), bnet.cnodes(:), evidence(:,t-1:t));
  end
end       

[engine.clpot, loglik] = enter_soft_evidence(engine, CPDpot, observed, pot_type, filter);

engine.filter = filter;
engine.T = T;