wolffd@0: function [f, logscale] = fwd(engine, fpast, ev, t)
wolffd@0: % Forwards pass.
wolffd@0: 
wolffd@0: f.obslik = mk_hmm_obs_lik_vec(engine, ev);
wolffd@0: transmat = engine.transprob;
wolffd@0: f.past_alpha = fpast.alpha;
wolffd@0: if engine.maximize
wolffd@0:   Q = length(fpast.alpha);
wolffd@0:   A = repmat(fpast.alpha, [1 Q]);
wolffd@0:   m = max(transmat .* A, [], 1);
wolffd@0:   [f.alpha, scale] = normalise(m(:) .* f.obslik);
wolffd@0: else
wolffd@0:   [f.alpha, scale] = normalise((transmat' * fpast.alpha) .* f.obslik);
wolffd@0: end
wolffd@0: logscale = log(scale);
wolffd@0: %f.xi = normalise((fpast.alpha * obslik') .* transmat); % t-1,t
wolffd@0: f.t = t;