from pystencils_walberla import Sweep

k = Sweep(dim=2)

src = k.field("f1")
dst = k.temporaryField(src)
h = k.constant("h")

rhs = (src[1,0] + src[-1,0] + src[0,1] + src[0, -1] ) / (4 * h**2)
k.addEq(dst[0,0], rhs)

k.generate()