.930817e+01, ||grad||_infty = 1.84e-01
Iter   200, f(x) = 3.930816e+01, ||grad||_infty = 1.81e-01
Iter   202, f(x) = 3.930816e+01, ||grad||_infty = 1.81e-01
</pre><h2 id="16">Check the output</h2><pre class="codeinput">exitmsg = output.ExitMsg
</pre><pre class="codeoutput">
exitmsg =

    'CONVERGENCE: REL_REDUCTION_OF_F_&lt;=_FACTR*EPSMCH.'

</pre><p>The fit is the percentage of the data that is explained by the model. Because we have noise, we do not expect the fit to be perfect.</p><pre class="codeinput"