The calculation repeats from the control_index until the data item value as specified by data_item_name data_item_index data_item_number satisfies repeat_criterium.
If repeat_criterium is -change then repeating is stopped if the value changes less than tolerance. The tolerance needs to be specified in the control_repeat_until_tolerance record (with the same index). It specifies as a percentage the relative change in the data item value above which repeating occurs.
If repeat_criterium is -value then repeating is stopped if the absolute value is less than tolerance. The tolerance needs to be specified in the control_repeat_until_tolerance record (with the same index).
This can typically be used to perform a number of refinements combined with time stepping to a new solution until some data item doesn't change much anymore.
See also control_repeat.