norm(z-y');

function err = fitexpgaussian(lambda,t,y,timeconstant)
%   Fitting functions for a exponentially-broadened Gaussian band spectrum.
%  T. C. O'Haver, October 23, 2006.
global c
A = zeros(length(t),round(length(lambda)/2));
for j = 1:length(lambda)/2,
    A(:,j) = expgaussian(t,lambda(2*j-1),lambda(2*j),timeconstant);
end
c = A\y';
z = A*c;
err = norm(z-y');