1*c4762a1bSJed BrownPetscAtan2Real(1.0,1.0) = 0.785398 2*c4762a1bSJed BrownPetscAtan2Real(1.0,0.0) = 1.5708 3*c4762a1bSJed BrownPetscAtan2Real(0.0,1.0) = 0. 4*c4762a1bSJed BrownPetscAtan2Real(0.0,0.0) = 0. 5