s constructed as Matlab cell array with curly brackets. At least the structure has, for each parameter, the name of the parameter and the initial value of it. Third optional parameter given below is the minimal accepted value. With it we set a positivity constraits for both of the parameters.</p><pre class="codeinput">params = {
    {<span class="string">'theta1'</span>, tmin(1), 0}
    {<span class="string">'theta2'</span>, tmin(2), 0}
    };
</pre><p>In general, each parameter line can have up to 7 elemen