Hi,
I am trying to implement a Newton method with the stopping criterium as the l2 norm of the residual from the non-linear form. However, when the norm of the residual is computed in each iteration
Code:
a.Apply(gfu.vec, res)
print("\t||res||_l2 = {:}".format(sqrt(InnerProduct(res,res))))
this does not converge to zero, even though the method converges (in the dual norm) and the update disappears. I have attached a MWE, (minimal adaptation of the iTutorial 3.7 on Nonlinear Problems).
As we are trying to solve a(u
h,v
h)=0, the residual ||a(u
hi, v
h) ||
l2 = ||res ||
l2 should converge towards zero. Doe anyone know, what is going wrong here?
Best wishes,
Henry