[Getdp] Characteristic function

sdurand sdurand at cage.ugent.be
Wed Jun 17 17:21:34 CEST 2009


Hello everybody,

I want to solve a 2D optimization problem in GetDP where the cost
functional is an integral over an inner domain (eg circle). Therefore, I
obtain an adjoint problem in which the right hand side is an integral
over this domain. Since this domain has the same material parameters as
its surroundings, I didn't define it as a separate region.

To calculate the integral over this domain, I have defined the
characteristic function as

Ie [domain] = ($X^2 + $Y^2 <= 4.) ? 1. : 0.;

such that the right hand side of my problem becomes

 Galerkin { [ Ie[]*({u}-{ud}), {p} ]; In domain;
	Jacobian Vol; Integration GradGrad; }

where u and ud are results from other calculations.

However, I always get the "Null right hand side"-error. Is it not
allowed in GetDP to use characteristic functions instead of Physical
Regions for integration?

Thank you,
Stephane


-- 
Stephane Durand
Department of Mathematical analysis
Research group of Numerical Functional Analysis and Mathematical
Modelling
Ghent University