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view toolboxes/FullBNT-1.0.7/bnt/CPDs/@hhmmQ_CPD/Old/hhmmQ_CPD.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 CPD = hhmmQ_CPD(bnet, self, Qnodes, d, D, varargin) % HHMMQ_CPD Make the CPD for a Q node at depth D of a D-level hierarchical HMM % CPD = hhmmQ_CPD(bnet, self, Qnodes, d, D, ...) % % Fd(t-1) \ Q1:d-1(t) % \ | % \ v % Qd(t-1) -> Qd(t) % / % / % Fd+1(t-1) % % We assume parents are ordered (numbered) as follows: % Qd(t-1), Fd+1(t-1), Fd(t-1), Q1(t), ..., Qd(t) % % The parents of Qd(t) can either be just Qd-1(t) or the whole stack Q1:d-1(t) (allQ) % In either case, we will call them Qps. % If d=1, Qps does not exist. Also, the F1(t-1) -> Q1(t) arc is optional. % If the arc is missing, startprob does not need to be specified, % since the toplevel is assumed to never reset (F1 does not exist). % If d=D, Fd+1(t-1) does not exist (there is no signal from below). % % optional args [defaults] % % transprob - transprob(i,k,j) = prob transition from i to j given Qps = k ['leftright'] % selfprob - prob of a transition from i to i given Qps=k [0.1] % startprob - startprob(k,j) = prob start in j given Qps = k ['leftstart'] % startargs - other args to be passed to the sub tabular_CPD for learning startprob % transargs - other args will be passed to the sub tabular_CPD for learning transprob % allQ - 1 means use all Q nodes above d as parents, 0 means just level d-1 [0] % F1toQ1 - 1 means add F1(t-1) -> Q1(t) arc, 0 means level 1 never resets [0] % % For d=1, startprob(1,j) is only needed if F1toQ1=1 % Also, transprob(i,j) can be used instead of transprob(i,1,j). % % hhmmQ_CPD is a subclass of tabular_CPD so we inherit inference methods like CPD_to_pot, etc. % % We create isolated tabular_CPDs with no F parents to learn transprob/startprob % so we can avail of e.g., entropic or Dirichlet priors. % In the future, we will be able to represent the transprob using a tree_CPD. % % For details, see "Linear-time inference in hierarchical HMMs", Murphy and Paskin, NIPS'01. ss = bnet.nnodes_per_slice; %assert(self == Qnodes(d)+ss); ns = bnet.node_sizes(:); CPD.Qsizes = ns(Qnodes); CPD.d = d; CPD.D = D; allQ = 0; % find out which parents to use, to get right size for i=1:2:length(varargin) switch varargin{i}, case 'allQ', allQ = varargin{i+1}; end end if d==1 CPD.Qps = []; else if allQ CPD.Qps = Qnodes(1:d-1); else CPD.Qps = Qnodes(d-1); end end Qsz = ns(self); Qpsz = prod(ns(CPD.Qps)); % set default arguments startprob = 'leftstart'; transprob = 'leftright'; startargs = {}; transargs = {}; CPD.F1toQ1 = 0; selfprob = 0.1; for i=1:2:length(varargin) switch varargin{i}, case 'transprob', transprob = varargin{i+1}; case 'selfprob', selfprob = varargin{i+1}; case 'startprob', startprob = varargin{i+1}; case 'startargs', startargs = varargin{i+1}; case 'transargs', transargs = varargin{i+1}; case 'F1toQ1', CPD.F1toQ1 = varargin{i+1}; end end Qps = CPD.Qps + ss; old_self = self-ss; if strcmp(transprob, 'leftright') LR = mk_leftright_transmat(Qsz, selfprob); transprob = repmat(reshape(LR, [1 Qsz Qsz]), [Qpsz 1 1]); % transprob(k,i,j) transprob = permute(transprob, [2 1 3]); % now transprob(i,k,j) end transargs{end+1} = 'CPT'; transargs{end+1} = transprob; CPD.sub_CPD_trans = mk_isolated_tabular_CPD([old_self Qps], ns([old_self Qps self]), transargs); S = struct(CPD.sub_CPD_trans); CPD.transprob = myreshape(S.CPT, [Qsz Qpsz Qsz]); if strcmp(startprob, 'leftstart') startprob = zeros(Qpsz, Qsz); startprob(:,1) = 1; end if (d==1) & ~CPD.F1toQ1 CPD.sub_CPD_start = []; CPD.startprob = []; else startargs{end+1} = 'CPT'; startargs{end+1} = startprob; CPD.sub_CPD_start = mk_isolated_tabular_CPD(Qps, ns([Qps self]), startargs); S = struct(CPD.sub_CPD_start); CPD.startprob = myreshape(S.CPT, [Qpsz Qsz]); end CPD = class(CPD, 'hhmmQ_CPD', tabular_CPD(bnet, self)); CPD = update_CPT(CPD);