diff options
Diffstat (limited to 'SD-VBS/common/toolbox/MultiNcut/gaussian.m')
-rwxr-xr-x | SD-VBS/common/toolbox/MultiNcut/gaussian.m | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/SD-VBS/common/toolbox/MultiNcut/gaussian.m b/SD-VBS/common/toolbox/MultiNcut/gaussian.m new file mode 100755 index 0000000..509b129 --- /dev/null +++ b/SD-VBS/common/toolbox/MultiNcut/gaussian.m | |||
@@ -0,0 +1,31 @@ | |||
1 | function p=gaussian(x,m,C); | ||
2 | % p=gaussian(x,m,C); | ||
3 | % | ||
4 | % Evaluate the multi-variate density with mean vector m and covariance | ||
5 | % matrix C for the input vector x. | ||
6 | % | ||
7 | % p=gaussian(X,m,C); | ||
8 | % | ||
9 | % Vectorized version: Here X is a matrix of column vectors, and p is | ||
10 | % a vector of probabilities for each vector. | ||
11 | |||
12 | d=length(m); | ||
13 | |||
14 | if size(x,1)~=d | ||
15 | x=x'; | ||
16 | end | ||
17 | N=size(x,2); | ||
18 | |||
19 | detC = det(C); | ||
20 | if rcond(C)<eps | ||
21 | % fprintf(1,'Covariance matrix close to singular. (gaussian.m)\n'); | ||
22 | p = zeros(N,1); | ||
23 | else | ||
24 | m=m(:); | ||
25 | M=m*ones(1,N); | ||
26 | denom=(2*pi)^(d/2)*sqrt(abs(detC)); | ||
27 | mahal=sum(((x-M)'*inv(C)).*(x-M)',2); % Chris Bregler's trick | ||
28 | numer=exp(-0.5*mahal); | ||
29 | p=numer/denom; | ||
30 | end | ||
31 | |||