comparison toolboxes/FullBNT-1.0.7/bnt/examples/dynamic/HHMM/Square/Old/learn_square_hhmm.m @ 0:e9a9cd732c1e tip

first hg version after svn

+% Learn a 3 level HHMM similar to mk_square_hhmm
+
+% Because startprob should be shared for t=1:T,
+% but in the DBN is shared for t=2:T, we train using a single long sequence.
+
+discrete_obs = 0;
+supervised = 1;
+obs_finalF2 = 0;
+% It is not possible to observe F2 if we learn
+% because the update_ess method for hhmmF_CPD and hhmmQ_CPD assume
+% the F nodes are always hidden (for speed).
+% However, for generating, we might want to set the final F2=true
+% to force all subroutines to finish.
+
+ss = 6;
+Q1 = 1; Q2 = 2; Q3 = 3; F3 = 4; F2 = 5; Onode = 6;
+Qnodes = [Q1 Q2 Q3]; Fnodes = [F2 F3];
+
+seed = 1;
+rand('state', seed);
+randn('state', seed);
+
+if discrete_obs
+  Qsizes = [2 4 2];
+else
+  Qsizes = [2 4 1];
+end
+
+D = 3;
+Qnodes = 1:D;
+startprob = cell(1,D);
+transprob = cell(1,D);
+termprob = cell(1,D);
+
+startprob{1} = 'unif';
+transprob{1} = 'unif';
+
+% In the unsupervised case, it is essential that we break symmetry
+% in the initial param estimates.
+%startprob{2} = 'unif';
+%transprob{2} = 'unif';
+%termprob{2} = 'unif';
+startprob{2} = 'rnd';
+transprob{2} = 'rnd';
+termprob{2} = 'rnd';
+
+leftright = 0;
+if leftright
+  % Initialise base-level models as left-right.
+  % If we initialise with delta functions,
+  % they will remain delat funcitons after learning
+  startprob{3} = 'leftstart';
+  transprob{3}  = 'leftright';
+  termprob{3} = 'rightstop';
+else
+  % If we want to be able to run a base-level model backwards...
+  startprob{3} = 'rnd';
+  transprob{3}  = 'rnd';
+  termprob{3} = 'rnd';
+end
+
+if discrete_obs
+  % Initialise observations of lowest level primitives in a way which we can interpret
+  chars = ['L', 'l', 'U', 'u', 'R', 'r', 'D', 'd'];
+  L=find(chars=='L'); l=find(chars=='l');
+  U=find(chars=='U'); u=find(chars=='u');
+  R=find(chars=='R'); r=find(chars=='r');
+  D=find(chars=='D'); d=find(chars=='d');
+  Osize = length(chars);
+  
+  p = 0.9;
+  obsprob = (1-p)*ones([4 2 Osize]);
+  %       Q2 Q3 O
+  obsprob(1, 1, L) =  p;
+  obsprob(1, 2, l) =  p;
+  obsprob(2, 1, U) =  p;
+  obsprob(2, 2, u) =  p;
+  obsprob(3, 1, R) =  p;
+  obsprob(3, 2, r) =  p;
+  obsprob(4, 1, D) =  p;
+  obsprob(4, 2, d) =  p;
+  obsprob = mk_stochastic(obsprob);
+  Oargs = {'CPT', obsprob};
+
+else
+  % Initialise means of lowest level primitives in a way which we can interpret
+  % These means are little vectors in the east, south, west, north directions.
+  % (left-right=east, up-down=south, right-left=west, down-up=north)
+  Osize = 2;
+  mu = zeros(2, Qsizes(2), Qsizes(3));
+  noise = 0;
+  scale = 3;
+  for q3=1:Qsizes(3)
+    mu(:, 1, q3) = scale*[1;0] + noise*rand(2,1);
+  end
+  for q3=1:Qsizes(3)
+    mu(:, 2, q3) = scale*[0;-1] + noise*rand(2,1);
+  end
+  for q3=1:Qsizes(3)
+    mu(:, 3, q3) = scale*[-1;0] + noise*rand(2,1);
+  end
+  for q3=1:Qsizes(3)
+    mu(:, 4, q3) = scale*[0;1] + noise*rand(2,1);
+  end
+  Sigma = repmat(reshape(scale*eye(2), [2 2 1 1 ]), [1 1 Qsizes(2) Qsizes(3)]);
+  Oargs = {'mean', mu, 'cov', Sigma, 'cov_type', 'diag'};
+end
+
+bnet = mk_hhmm('Qsizes', Qsizes, 'Osize', Osize', 'discrete_obs', discrete_obs,...
+	       'Oargs', Oargs, 'Ops', Qnodes(2:3), ...
+	       'startprob', startprob, 'transprob', transprob, 'termprob', termprob);
+
+if supervised
+  bnet.observed = [Q1 Q2 Onode];
+else
+  bnet.observed = [Onode];
+end
+
+if obs_finalF2
+  engine = jtree_dbn_inf_engine(bnet);
+  % can't use ndx version because sometimes F2 is hidden, sometimes observed
+  error('can''t observe F when learning')
+else
+  if supervised
+    engine = jtree_ndx_dbn_inf_engine(bnet);
+  else
+    engine = jtree_hmm_inf_engine(bnet);
+  end
+end
+  
+if discrete_obs
+  % generate some synthetic data (easier to debug)
+  cases = {};
+
+  T = 8;
+  ev = cell(ss, T);
+  ev(Onode,:) = num2cell([L l U u R r D d]);
+  if supervised
+    ev(Q1,:) = num2cell(1*ones(1,T));
+    ev(Q2,:) = num2cell( [1 1 2 2 3 3 4 4]);
+  end
+  cases{1} = ev;
+  cases{3} = ev;
+    
+  T  = 8;
+  ev = cell(ss, T);
+  if leftright % base model is left-right
+    ev(Onode,:) = num2cell([R r U u L l D d]);
+  else
+    ev(Onode,:) = num2cell([r R u U l L d D]);
+  end
+  if supervised
+    ev(Q1,:) = num2cell(2*ones(1,T));
+    ev(Q2,:) = num2cell( [3 3 2 2 1 1 4 4]);
+  end
+    
+  cases{2} = ev;
+  cases{4} = ev;
+
+  if obs_finalF2
+    for i=1:length(cases)
+      T = size(cases{i},2);
+      cases{i}(F2,T)={2}; % force F2 to be finished at end of seq
+    end
+  end
+
+  if 0
+    ev = cases{4};
+    engine2 = enter_evidence(engine2, ev);
+    T = size(ev,2);
+    for t=1:T
+      m=marginal_family(engine2, F2, t);
+      fprintf('t=%d\n', t);
+      reshape(m.T, [2 2])
+    end
+  end
+  
+  %  [bnet2, LL] = learn_params_dbn_em(engine, cases, 'max_iter', 10);
+  long_seq = cat(2, cases{:});
+  [bnet2, LL, engine2] = learn_params_dbn_em(engine, {long_seq}, 'max_iter', 200);
+  
+  % figure out which subsequence each model is responsible for
+  mpe = calc_mpe_dbn(engine2, long_seq);
+  pretty_print_hhmm_parse(mpe, Qnodes, Fnodes, Onode, chars);
+
+else
+  load 'square4_cases' % cases{seq}{i,t} for i=1:ss 
+  %plot_square_hhmm(cases{1})
+  %long_seq = cat(2, cases{:});
+  train_cases = cases(1:2);
+  long_seq = cat(2, train_cases{:});
+  if ~supervised
+    T = size(long_seq,2);
+    for t=1:T
+      long_seq{Q1,t} = [];
+      long_seq{Q2,t} = [];
+    end
+  end
+  [bnet2, LL, engine2] = learn_params_dbn_em(engine, {long_seq}, 'max_iter', 100);
+
+  CPDO=struct(bnet2.CPD{eclass(Onode,1)});
+  mu = CPDO.mean;
+  Sigma = CPDO.cov;
+  CPDO_full = CPDO;
+  
+  % force diagonal covs after training
+  for k=1:size(Sigma,3)
+    Sigma(:,:,k) = diag(diag(Sigma(:,:,k)));
+  end
+  bnet2.CPD{6} = set_fields(bnet.CPD{6}, 'cov', Sigma);
+  
+  if 0
+  % visualize each model by concatenating means for each model for nsteps in a row
+  nsteps = 5;
+  ev = cell(ss, nsteps*prod(Qsizes(2:3)));
+  t = 1;
+  for q2=1:Qsizes(2)
+    for q3=1:Qsizes(3)
+      for i=1:nsteps
+	ev{Onode,t} = mu(:,q2,q3);
+	ev{Q2,t} = q2;
+	t = t + 1;
+      end
+    end
+  end
+  plot_square_hhmm(ev)      
+  end
+
+  % bnet3 is the same as the learned model, except we will use it in testing mode
+  if supervised
+    bnet3 = bnet2;
+    bnet3.observed = [Onode];
+    engine3 = hmm_inf_engine(bnet3);
+    %engine3 = jtree_ndx_dbn_inf_engine(bnet3);
+  else
+    bnet3 = bnet2;
+    engine3 = engine2;
+  end
+  
+  if 0
+  % segment whole sequence
+  mpe = calc_mpe_dbn(engine3, long_seq);
+  pretty_print_hhmm_parse(mpe, Qnodes, Fnodes, Onode, []);
+  end
+  
+  % segment each sequence
+  test_cases = cases(3:4);
+  for i=1:2
+    ev = test_cases{i};
+    T = size(ev, 2);
+    for t=1:T
+      ev{Q1,t} = [];
+      ev{Q2,t} = [];
+    end
+    mpe = calc_mpe_dbn(engine3, ev);
+    subplot(1,2,i)
+    plot_square_hhmm(mpe)      
+    %pretty_print_hhmm_parse(mpe, Qnodes, Fnodes, Onode, []);
+    q1s = cell2num(mpe(Q1,:));
+    h = hist(q1s, 1:Qsizes(1));
+    map_q1 = argmax(h);
+    str = sprintf('test seq %d is of type %d\n', i, map_q1);
+    title(str)
+  end
+
+end
+
+if 0
+% Estimate gotten by couting transitions in the labelled data
+% Note that a self transition shouldnt count if F2=off.
+Q2ev = cell2num(ev(Q2,:));
+Q2a = Q2ev(1:end-1);
+Q2b = Q2ev(2:end);
+counts = compute_counts([Q2a; Q2b], [4 4]);
+end
+
+eclass = bnet2.equiv_class;
+CPDQ1=struct(bnet2.CPD{eclass(Q1,2)});
+CPDQ2=struct(bnet2.CPD{eclass(Q2,2)});
+CPDQ3=struct(bnet2.CPD{eclass(Q3,2)});
+CPDF2=struct(bnet2.CPD{eclass(F2,1)});
+CPDF3=struct(bnet2.CPD{eclass(F3,1)});
+
+
+A=add_hhmm_end_state(CPDQ2.transprob, CPDF2.termprob(:,:,2));
+squeeze(A(:,1,:))
+squeeze(A(:,2,:))
+CPDQ2.startprob
+ 
+if 0
+S=struct(CPDF2.sub_CPD_term);
+S.nsamples
+reshape(S.counts, [2 4 2])
+end