PDFGMM |
Evaluates gaussian mixture model.
Synopsis:
y = pdfgmm(X, model )
Description:
This function evaluates a probability density function
determined by Gaussian mixture model (GMM) for given input column
vectors in X. The GMM is defined as
y(i) = sum model.Prior(j)*pdfgauss(X(:,i),model.Mean(:,j),model.Cov(:,:,j))
j=1:ncomp
for all i=1:size(X,2).
Input:
X [dim x num_data] Input matrix of column vectors.
model.Mean [dim x ncomp] Means of Gaussians.
model.Cov [dim x dim x ncomp] Covarince matrices.
model.Prior [ncomp x 1] Weights of components.
Output:
y [1 x num_data] Values of probability density function.
Example:
Univariate case
x = linspace(-5,5,100);
distrib = struct('Mean',[-2 3],'Cov',[1 0.5],'Prior',[0.4 0.6]);
y = pdfgmm(x,distrib);
figure; plot(x,y);
Multivariate case
model.Mean(:,1) = [-1;-1]; model.Cov(:,:,1) = [1,0.5;0.5,1];
model.Mean(:,2) = [1;1]; model.Cov(:,:,2) = [1,-0.5;-0.5,1];
model.Prior = [0.4 0.6];
[Ax,Ay] = meshgrid(linspace(-5,5,100), linspace(-5,5,100));
y = pdfgmm([Ax(:)';Ay(:)'],model);
figure; surf( Ax, Ay, reshape(y,100,100)); shading interp;
See also
GMMSAMP, PDFGAUSS.
About: Statistical Pattern Recognition Toolbox
(C) 1999-2003, Written by Vojtech Franc and Vaclav Hlavac
Czech Technical University Prague
Faculty of Electrical Engineering
Center for Machine Perception
Modifications:
28-apr-2004, VF