title: How to set the stopping criterion of Matlab's fmincon to "output.stepsize" when "active-set" algorithm is used
body: <p>How can the <code>output.stepsize</code> be used as a stopping criterion for <code>fmincon</code> when using the <code>'active-set'</code> algorithm?</p>
  
  <p>When I tried to solve a nonlinear constrained non-convex optimization problem, I observed that the <code>output.stepsize</code> option within <code>'PlotFcns'</code> would be a better stopping criterion than the tolerances or maximum evaluations. But in the options argument structure, there is no such option.</p>
  
  <p>I also noticed that <code>fmincon</code> uses <code>nonlcon</code> to solve the problem where <code>output.stepsize</code> is calcualted.</p>
  
  <p>If I don't want to change the original code of either <code>fmincon</code> or <code>nonlcon</code>, how can I set an upper limit for <code>output.stepsize</code> to use as a stopping criterion for my optimization run?</p>