function y = gauss(mu, covar, x)%GAUSS	Evaluate a Gaussian distribution.%%	Description%%	Y = GAUSS(MU, COVAR, X) evaluates a multi-variate Gaussian  density%	in D-dimensions at a set of points given by the rows of the matrix X.%	The Gaussian density has mean vector MU and covariance matrix COVAR.%%	See also%	GSAMP, DEMGAUSS%%	Copyright (c) Ian T Nabney (1996-2001)[n, d] = size(x);[j, k] = size(covar);% Check that the covariance matrix is the correct dimensionif ((j ~= d) | (k ~=d))  error('Dimension of the covariance matrix and data should match');end   invcov = inv(covar);mu = reshape(mu, 1, d);    % Ensure that mu is a row vectorx = x - ones(n, 1)*mu;fact = sum(((x*invcov).*x), 2);y = exp(-0.5*fact);y = y./sqrt((2*pi)^d*det(covar));