# 12.1. Implicit Solver Control Contact Options

    BEGIN CONTROL CONTACT
      CONTROL SUBSET = <list> controlTypes(ADAGIO, ARS, JAS)
    END [CONTROL CONTACT]

The `CONTROL SUBSET` command restricts a control contact block to only apply to some contact enforcement types. The options to the command are ADAGIO to control kinematic and augmented Lagrange contact, JAS to control JAS mode contact, and ARS (Goodyear specific) to control analytic rigid surface contact. By default, the control contact block applies to all three contact types. Use of the control subset logic may be useful if it is desired to have the different enforcement types use different control contact option sets.

The `CONTROL CONTACT` block is described in the Sierra/SM User Manual.

The `AREA UPDATE FREQUENCY` is a performance option used to control how often the analytic contact surfaces update the local areas and normal directions. Updating these values more frequency (lower `numStep`) may lower performance but yield greater accuracy (especially in derived output quantities such as contact traction).

If the `CONTACT FORCE PREDICTOR` option is on the previous step contact forces will be used as an initial guess to the current step contact forces. This could improve results if the contact forces are stable step to step or make results worse if the contact forces are highly volatile. The default value for this option is `ON` as ARS contact is often used to model mostly static contacts.