wehub-resource-sync
31 lines
1.0 KiB
Matlab
Executable File
31 lines
1.0 KiB
Matlab
Executable File
function [nodeBel, edgeBel] = mrfMeanField(A, nodePot, edgePot, epoch)
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% Mean field for MRF (Assuming that egdePot is symmetric)
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% p(x)=exp(-E(x))/Z, E(x)=\sum(edgePot)+sum(nodePot)
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% Input:
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% A: n x n adjacent matrix of undirected graph, where value is edge index
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% nodePot: k x n node potential
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% edgePot: k x k x m edge potential
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% Output:
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% nodeBel: k x n node belief q(x_i)
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% edgeBel: k x k x m edge belief q(x_i,x_j)
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% Written by Mo Chen (sth4nth@gmail.com)
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tol = 0;
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if nargin < 4
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epoch = 50;
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tol = 1e-8;
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end
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[nodeBel,L] = softmax(-nodePot,1); % init nodeBel
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for iter = 1:epoch
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nodeBel0 = nodeBel;
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for i = 1:numel(L)
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[~,j,e] = find(A(i,:)); % neighbors
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nodeBel(:,i) = softmax(-nodePot(:,i)-reshape(edgePot(:,:,e),2,[])*reshape(nodeBel(:,j),[],1));
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end
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if max(abs(nodeBel(:)-nodeBel0(:))) < tol; break; end
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end
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[s,t,e] = find(tril(A));
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edgeBel = zeros(size(edgePot));
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for l = 1:numel(e)
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edgeBel(:,:,e(l)) = nodeBel(:,s(l))*nodeBel(:,t(l))';
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end |