Not built-in. Personally in my client app(s) I always lay result cells on a table, and I do those calculations on top of such tables.
I don't know if there is some standard for that at any level. In the OLAP materials I've read that need is not usually even mentioned, or is left up to the reporting/visualization tool. Also afaik standards like MDX don't contemplate that explicitly, besides allowing subqueries.