comparison toolboxes/FullBNT-1.0.7/bnt/potentials/@scgpot/complement_pot.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function [margpot, comppot] = complement_pot(pot, keep)
+% COMPLEMENT_POT complement means decompose of a potential into its strong marginal and 
+% its complement corresponds exactly to the decomposition of a probability distribution 
+% into its marginal and conditional
+% [margpot, comppot] = complement_pot(pot, keep)
+
+% keep can only include continuous head nodes and discrete nodes
+% margpot is the stable CG potential of keep nodes
+% comppot is the stable CG potential of others in corresponds exactly to 
+% the discomposition of a probability distribution of its marginal and conditional
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Calculation of the marginal requires integration over      %
+% all variables in csumover. Thus cheadkeep contains all     %
+% continuous variables in the marginal potential             %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%keyboard;
+csumover = mysetdiff(pot.cheaddom, keep);
+cheadkeep = mysetdiff(pot.cheaddom, csumover);
+
+nodesizes = zeros(1, max(pot.domain));
+nodesizes(pot.ddom) = pot.dsizes;
+nodesizes(pot.cheaddom) = pot.cheadsizes;
+nodesizes(pot.ctaildom) = pot.ctailsizes;
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Description of the variables in the marginal domain        %
+% For the calculation of a strong marginal first integration %
+% over all continuous variables in the head takes place.     %
+% The calculation of the marginal over the head variables    %
+% might result in a smaller or empty tail                    %
+% If there are no head variables, and therefore no tail      %
+% variables, left marginalisation over discrete variables    %
+% may take place                                             %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  
+margdom      = mysetdiff(pot.domain,keep);
+% margddom   = pot.ddom;
+margcheaddom = cheadkeep;
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Marginalisation over discrete variables is only allowed when %
+% the tail is empty                                            %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+margddom = myintersect(pot.ddom,keep);               % Discrete domain of marginal
+margctaildom = myintersect(pot.ctaildom,keep);       % Tail domain
+assert(isempty(mysetdiff(pot.ddom,margddom)) | isempty(margctaildom))  
+
+
+%margctaildom = pot.ctaildom;
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Even if marginalisation over continuous variables is only defined %
+% for head variables, the marginalisation over haed-variables might %
+% result in a smaller tail                                          %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+margctaildom = myintersect(pot.ctaildom,keep);
+
+margcheadsizes = nodesizes(margcheaddom);
+margcheadsize = sum(margcheadsizes);
+margctailsizes = nodesizes(margctaildom);
+margctailsize = sum(margctailsizes);
+
+compdom = pot.domain;
+compddom = pot.ddom;
+compcheaddom = csumover;
+compctaildom = myunion(pot.ctaildom, cheadkeep);
+compcheadsizes = nodesizes(compcheaddom);
+compcheadsize = sum(compcheadsizes);
+compctailsizes = nodesizes(compctaildom);
+compctailsize = sum(compctailsizes);
+
+dkeep = myintersect(pot.ddom, keep);
+%if dom is only contain discrete node
+if isempty(pot.cheaddom)
+    dsumover = mysetdiff(pot.ddom, dkeep);
+    
+    if isempty(dsumover)
+        margpot = pot;
+        comppot = scgpot([], [], [], []);
+        return;
+    end
+        
+    
+    I = prod(nodesizes(dkeep));
+    J = prod(nodesizes(dsumover));
+    sum_map = find_equiv_posns(dsumover, pot.ddom);
+    keep_map = find_equiv_posns(dkeep, pot.ddom);
+    iv = zeros(1, length(pot.ddom)); % index vector
+    p1 = zeros(I,J);
+    for i=1:I
+        keep_iv = ind2subv(nodesizes(dkeep), i);
+        iv(keep_map) = keep_iv;
+        for j=1:J
+            sum_iv = ind2subv(nodesizes(dsumover), j);
+            iv(sum_map) = sum_iv;
+            k = subv2ind(nodesizes(pot.ddom), iv);
+            potc = struct(pot.scgpotc{k}); % violate object privacy
+            p1(i,j) = potc.p;
+        end
+    end
+    p2 = sum(p1,2);
+    p2 = p2 + (p2==0)*eps;
+    
+    margscpot = cell(1, I);
+    compscpot = cell(1, I*J);
+    iv = zeros(1, length(pot.ddom)); % index vector
+    for i=1:I
+        margscpot{i} = scgcpot(0, 0, p2(i));
+        keep_iv = ind2subv(nodesizes(dkeep), i);
+        iv(keep_map) = keep_iv;
+        for j=1:J
+            sum_iv = ind2subv(nodesizes(dsumover), j);
+            iv(sum_map) = sum_iv;
+            k = subv2ind(nodesizes(pot.ddom), iv);
+            q = p1(i,j)/p2(i);
+            compscpot{k} = scgcpot(0, 0, q);
+        end
+    end
+    
+    margpot = scgpot(dkeep, [], [], nodesizes, margscpot);
+    comppot = scgpot(pot.ddom, [], [], nodesizes,compscpot);
+    return;
+end
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% head of the potential is not empty %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+dsize = pot.dsize;
+compscpot = cell(1, dsize);
+
+fmaskh = find_equiv_posns(margcheaddom, compctaildom);
+fmaskt = find_equiv_posns(margctaildom, compctaildom);
+
+fh = block(fmaskh, compctailsizes);
+ft = block(fmaskt, compctailsizes);
+
+
+if ~isempty(margcheaddom)
+    for i=1:dsize
+        potc = struct(pot.scgpotc{i});
+        q = 1;
+        p = potc.p;
+        [A1, A2, B1, B2, C11, C12, C21, C22] = partition_matrix_vec_3(potc.A, potc.B, potc.C, margcheaddom, compcheaddom, nodesizes);
+
+        if ~isempty(margcheaddom)
+            margscpot{i} = scgcpot(margcheadsize, margctailsize, p, A1, B1, C11);
+        else
+            margscpot{i} = scgcpot(margcheadsize, margctailsize, p);
+        end 
+    
+        if ~isempty(compcheaddom)
+            if ~isempty(margcheaddom)
+                E = A2 - C21*pinv(C11)*A1;
+                tmp1 = C21*pinv(C11);
+                tmp2 = B2 - C21*pinv(C11)*B1;
+                F = zeros(compcheadsize, compctailsize);
+                F(:, fh) = tmp1;
+                F(:, ft) = tmp2;
+                G = C22 - C21*pinv(C11)*C12;
+            else
+                E = A2;
+                F = B2;
+                G = C22;
+            end
+            compscpot{i} = scgcpot(compcheadsize, compctailsize, q, E, F, G);
+        else
+            compscpot{i} = scgcpot(compcheadsize, 0, q);
+        end
+        if isempty(margcheaddom)
+            margpot = scgpot(margddom, [], [], nodesizes, margscpot);
+        else
+            margpot = scgpot(margddom, margcheaddom, margctaildom, nodesizes, margscpot);
+        end
+    end
+else
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    % Marginalisation took place over all head variables.                               %
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    % Calculate the strong marginal %
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    margpot = marginalize_pot(pot,keep);
+    mPot    = struct(margpot); 
+    for i =1:dsize
+        potc = struct(pot.scgpotc{i});  
+        % Get the probability of the original potential % 
+	q = potc.p;
+         
+        % Get the configuration defined by the index i%
+        config = ind2subv(pot.dsizes,i);
+        
+        % Calculate the corresponding configuration in the marginal potential
+        if isempty(margpot.dsizes)
+            % keep == []
+	    indMargPot = 1;
+        else
+            equivPos   = find_equiv_posns(dkeep,pot.ddom);
+            indMargPot = subv2ind(margpot.dsizes,config(equivPos));
+        end
+        % Figure out the corresponding marginal potential
+        mPotC = struct(mPot.scgpotc{indMargPot});
+        p = mPotC.p;
+        if p == 0
+            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+            % The following assignment is correct as p is only zero if q is also zero %
+            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+            compscpot{i} = scgcpot(compcheadsize,compctailsize,0,potc.A,potc.B,potc.C);
+        else
+            compscpot{i} = scgcpot(compcheadsize,compctailsize,q/p,potc.A,potc.B,potc.C);
+        end
+    end
+end
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% Put all components in one potential %
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+if isempty(compcheaddom)
+    comppot = scgpot(compddom, [], [], nodesizes,compscpot);
+else
+    comppot = scgpot(compddom, compcheaddom, compctaildom, nodesizes,compscpot);
+end
+
+