Convergence criteria

Is your feature request related to a problem? Please describe. Currently, only fixed number of iteration can be set to the optimizer. However, a convergence criteria would be useful.

Describe the solution you'd like By using a convergence criteria, a maximum number of steps OR the convergence criteria could be used to stop the iteration (whichever happens first). The reason why the iteration stopped should be available after the execution.

Are you able and willing to implement this feature yourself and open a pull request?

• Yes, I can provide this feature.

If anyone can do this issue, that would be great, however, I'm also fine with doing it myself in a form of PR.