Among a strong cast, Sam Rockwell is a standout in “Seven Psychopaths.” It’s not that the performances from Christopher Walken, Woody Harrelson and Colin Farrell were lacking. They’re all good, but Rockwell’s character has the most to work with.

“Seven Psychopaths” is an ultraviolent comedy. As with “Pulp Fiction” and similar films, the audience goes from repulsion to chuckles (or vice versa) in seconds. Some of its elements are serious. We see innocent people meet violent ends. But soon after, absurd events or remarks bring us right back to the funny.

Farrell plays an alcoholic screenwriter in L.A. who has an idea for a movie called “Seven Psychopaths,” but just can’t get started. Walken and Rockwell are dog kidnappers who then respond to “lost dog” postings to collect rewards. Harrelson is a hood whose Shih Tzu, Bonny, is taken.

Walken and Rockwell provide Farrell with ideas for the movie’s plot—the one he’s writing, that is. Some of the elements discussed for that screenplay do turn up in the movie we’re watching. The trio takes refuge in the desert after Rockwell kills his girlfriend (who is also Woody’s girlfriend). Woody, meanwhile, wants his dog back.

Among the supporting cast is Tom Waits as a psychopath who shares his personal story with Farrell about the killing he’s done. Gabourey “Precious” Sidibe appears briefly as Woody’s careless dog walker.

“Seven Psychopaths” benefits from the strong quartet of leads, each of whom has been in absurd comedies before. Each man has a commanding screen presence and, as a group, they help the movie over a bumpy section or two.

Worth noting are a couple of fantasy sequences (involving a graveyard shootout and a Vietnamese holy man) that add compelling action.

Writer/director Martin MacDonagh (who also wrote and directed “In Bruges” in ’08) has put together an totally entertaining movie. Its violence makes it off-limits for the squeamish, but for the rest of us, it’s fun.