def presmoother(self,A,x,b): gauss_seidel(A,x,b,iterations=1,sweep="forward")
def postsmoother(self,A,x,b): gauss_seidel(A,x,b,iterations=1,sweep="backward")
def smoother(A, x, b): relaxation.gauss_seidel(A, x, b, iterations=iterations, sweep=sweep)