l2 norm output

pressure error 1d: 0.0510736
pressure error 2d: 0.0383578
pressure error 3d: 0
velocity error 1d: 0.261247
velocity error 2d: 2.78397
velocity error 3d: 0
masked velocity error 2d: 0
div error 1d: 45.2166
div error 2d: 2
div error 3d: 0