l2 norm output

pressure error 1d: 0.0342404
pressure error 2d: 0.057298
pressure error 3d: 0
velocity error 1d: 1.02767
velocity error 2d: 5.32717
velocity error 3d: 0
masked velocity error 2d: 2.3391
div error 1d: 29.5274
div error 2d: 222.522
div error 3d: 0