expdecaydata;                               % generate data
close all;

cs = 0.5:0.02:1.5;                          % range of c values
taus = 4.0:0.2:16.0;                        % range of tau values
msesurf = zeros(length(taus), length(cs));  % mean squared error
for i = 1:length(taus)
    for k = 1:length(cs)
        msesurf(i, k) = mean((voltage - ...
                              exp2func(time, [cs(k), taus(i)])).^2);
    end
end
%surface(cs, taus, mses)
%contour(cs, taus, mses)
contourf(cs, taus, log10(msesurf))