Museums seem to always be on the lookout for new ways to group and exhibit the artwork already available to them in their permanent collection. Earlier this month, MoMA opened “Abstract Expressionists New York,” with pieces “drawn entirely from the Museum’s vast holdings” – not that there’s anything wrong with that; They bought those pieces for a reason and might as well show them off. MoCA will follow suit later this week with “The Artist’s Museum.” The title of the exhibition is a bit misleading; There’s no separate museum, it’s only meant to connote that the exhibition won’t be focusing on a particular movement but on a particular group of artists, Los Angeles-based artists, of course, from 1980-2010. They leave it to you to find a common thread.