spm_MH_reml_likelihood.m
31022b3a13e6master

spm_MH_reml_likelihood.m
View Options

			function [L] = spm_MH_reml_likelihood(h,Y,M);
			% likelihood function for spm_MH_reml
			% FORMAT [L] = spm_MH_reml_likelihood(h,Y,M);
			%
			% h - hyperparameters
			% Y - residual covariance
			%
			% L - likelihood p(Y,P)
			%__________________________________________________________________________
			% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

			% Karl Friston
			% $Id: spm_MH_reml_likelihood.m 1143 2008-02-07 19:33:33Z spm $

			% likelihood function
			%--------------------------------------------------------------------------
			n = length(Y);
			m = length(M.Q);

			% compute current estimate of covariance
			%--------------------------------------------------------------------------
			C = sparse(n,n);
			for i = 1:m
			if M.OPT
			C = C + M.Q{i}*exp(h(i));
			else
			C = C + M.Q{i}*h(i);
			end
			end
			iC = inv(C);

			% log p(Y,P\|M)
			%--------------------------------------------------------------------------
			e = h - M.hE;
			L = ...
			- trace(iC*Y)/2 ...
			- e'M.hPe/2 ...
			- M.Nnlog(2*pi)/2 ...
			- mlog(2pi)/2 ...
			- M.N*spm_logdet(C)/2 ...
			+ spm_logdet(M.hP)/2;

			% p(Y,P\|M)
			%--------------------------------------------------------------------------
			L = exp(L);