Daniel@0: function CPT = noisyORtoTable(inhibit, leak_inhibit)
Daniel@0: % NOISYORTOTABLE Convert noisyOR distribution to CPT
Daniel@0: % function CPT = noisyORtoTable(inhibit, leak_inhibit)
Daniel@0: %
Daniel@0: % inhibit(i) = prob i'th parent will be inhibited (flipped from 1 to 0)
Daniel@0: % leak_inhibit - optional suppression of leak
Daniel@0: % CPT(U1,...,Un, X) = Pr(X|U1,...,Un) where the Us are the parents (excluding leak).
Daniel@0: % State 1 = off, 2 = on
Daniel@0: 
Daniel@0: if nargin < 2, leak_inhibit = 1; end
Daniel@0: 
Daniel@0: q = [leak_inhibit inhibit(:)'];
Daniel@0: 
Daniel@0: if length(q)==1
Daniel@0:   CPT = [q  1-q];
Daniel@0:   return;
Daniel@0: end
Daniel@0: 
Daniel@0: n = length(q);
Daniel@0: Bn = ind2subv(2*ones(1,n), 1:(2^n))-1;  % all n bit vectors, with the left most column toggling fastest (LSB)
Daniel@0: CPT = zeros(2^n, 2);
Daniel@0: % Pr(X=0 | U_1 .. U_n) = prod_{i: U_i = on} q_i =  prod_i q_i ^ U_i = exp(u' * log(q_i))
Daniel@0: % This method is problematic when q contains zeros
Daniel@0: 
Daniel@0: Q = repmat(q(:)', 2^n, 1);
Daniel@0: Q(logical(~Bn)) = 1;
Daniel@0: CPT(:,1) = prod(Q,2);
Daniel@0: CPT(:,2) = 1-CPT(:,1);
Daniel@0: 
Daniel@0: CPT = reshape(CPT(2:2:end), 2*ones(1,n)); % skip cases in which the leak is off       
Daniel@0: 
Daniel@0: