40 lines
785 B
Matlab
40 lines
785 B
Matlab
function [R, Tr, S] = rigidfac(P, MD)
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% [R, Tr, S] = rigidfac(P, MD)
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%
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% Computes rank 3 factorization: P = R*S + Tr
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Pnew = P;
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[T, J] = size(Pnew); T = T/2;
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if sum(MD(:)) > 0, % if there is missing data, then it uses an iterative solution to get a rough initialization for the missing points
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[i,j] = find(MD==1);
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ind = sub2ind(size(P), [i; i+T], [j; j]);
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numIter = 10;
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else
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numIter = 1;
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ind = [];
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end
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r = 3;
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for iter=1:numIter,
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Tr = Pnew*ones(J,1)/J;
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Pnew_c = Pnew - Tr*ones(1,J);
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[a,b,c] = svd(Pnew_c,0);
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smallb = b(1:r,1:r);
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sqrtb = sqrt(smallb);
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Rhat = a(:,1:r) * sqrtb;
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Shat = sqrtb * c(:,1:r)';
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P_approx = Rhat*Shat + Tr*ones(1,J);
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Pnew(ind) = P_approx(ind);
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end
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G = findG(Rhat);
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R = Rhat*G;
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S = inv(G)*Shat;
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