Patrick Schwarzenegger Goes Solo to Coachella ... Miley Miles Away (PHOTOS)

Patrick Schwarzenegger was all smiles at Coachella Friday ... Miley Cyrus was kinda smiling too, but it seems they were in a different zip code.

Patrick was front and center at the H&M party, mugging with a random dude, while Miley was in a studio with producer Mike Will.

Seems a little strange. Coachella is the place we expected to see the 2 of them together.

We've gotten them together 2 times since Patrick's epic Spring break trip to Cabo and they seemed tight enough.