Criterion

What is a Criterion? The Criterion, as the name implies, is some sort of criterion that may or may not be satisfied by some quantities of the model.

The main motivation to have a Criterion is to terminate the ArcLength analysis. In a typical ArcLength analysis, neither the displacement nor the resistance is known in advance. There should be a way to determine when to stop the analysis.

A Criterion provides such a functionality. If the Criterion is satisfied, an exit flag will be sent out so that the analysis will stop.

Due to its designed functionality, a Criterion can also be used to early-stop the analysis.