Mercurial > hg > camir-aes2014
annotate toolboxes/FullBNT-1.0.7/KPMtools/sqdist.m @ 0:e9a9cd732c1e tip
first hg version after svn
| author | wolffd |
|---|---|
| date | Tue, 10 Feb 2015 15:05:51 +0000 |
| parents | |
| children |
| rev | line source |
|---|---|
| wolffd@0 | 1 function m = sqdist(p, q, A) |
| wolffd@0 | 2 % SQDIST Squared Euclidean or Mahalanobis distance. |
| wolffd@0 | 3 % SQDIST(p,q) returns m(i,j) = (p(:,i) - q(:,j))'*(p(:,i) - q(:,j)). |
| wolffd@0 | 4 % SQDIST(p,q,A) returns m(i,j) = (p(:,i) - q(:,j))'*A*(p(:,i) - q(:,j)). |
| wolffd@0 | 5 |
| wolffd@0 | 6 % From Tom Minka's lightspeed toolbox |
| wolffd@0 | 7 |
| wolffd@0 | 8 [d, pn] = size(p); |
| wolffd@0 | 9 [d, qn] = size(q); |
| wolffd@0 | 10 |
| wolffd@0 | 11 if nargin == 2 |
| wolffd@0 | 12 |
| wolffd@0 | 13 pmag = sum(p .* p, 1); |
| wolffd@0 | 14 qmag = sum(q .* q, 1); |
| wolffd@0 | 15 m = repmat(qmag, pn, 1) + repmat(pmag', 1, qn) - 2*p'*q; |
| wolffd@0 | 16 %m = ones(pn,1)*qmag + pmag'*ones(1,qn) - 2*p'*q; |
| wolffd@0 | 17 |
| wolffd@0 | 18 else |
| wolffd@0 | 19 |
| wolffd@0 | 20 if isempty(A) | isempty(p) |
| wolffd@0 | 21 error('sqdist: empty matrices'); |
| wolffd@0 | 22 end |
| wolffd@0 | 23 Ap = A*p; |
| wolffd@0 | 24 Aq = A*q; |
| wolffd@0 | 25 pmag = sum(p .* Ap, 1); |
| wolffd@0 | 26 qmag = sum(q .* Aq, 1); |
| wolffd@0 | 27 m = repmat(qmag, pn, 1) + repmat(pmag', 1, qn) - 2*p'*Aq; |
| wolffd@0 | 28 |
| wolffd@0 | 29 end |