On Tuesday January 18 2011 06:33:31 Anders Logg wrote: > Can somone remind me why we have sub() instead of [] for accessing > subspaces in Python?
This is because the way UFL handles Indexed(*). We have not (yet) managed to figure out how we can inherit (dynamic or static) from and Indexed(*). We need this when the resulting subfunction is returned. So therefore is [] used in ufl forms and .sub when a dolfin.SubFunction is needed. I am also not sure it would work to extract a SubFunction and then let it inherite Indexed(Coefficient(MixedElement(*))) as UFL assume it is an index into a MixedFunction. If the underlaying dolfin.Function is a SubFunction the indexing might get screwed. It might be possible with some magic to recognize a passed Indexed(Coefficient(MixedElement(*))) and then extract the dolfin.SubFunction when that is needed. It is magic but might work if the number of occasions it is used is limited. We might also just keep .sub for direct access to the SubFunction. In what places do we need a SubFunction? Johan _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
