function P = gaussdensity(rgb, train)
    MN = mean(train);
    CV = cov(train);
    
   coeff = 1 / ( (2*pi)^(3/2) * sqrt(norm(CV)) );
   
   xMinusMN = rgb - repmat(MN, size(rgb,1), 1);
   EXPON1 = xMinusMN * inv(CV).';
   EXPON2 = dot(xMinusMN.',EXPON1.');
   EXPON3 = exp( (-1/2)*EXPON2 );
   P = coeff*EXPON3;
   %EXPON3