Solver parameters

The GMRES method is used to solve the following linear system for the polarisability, $P(\omega)$,

$$\left \{ \begin{array}{l} \displaystyle P(\omega) = \sum_{i... ...ega) =\chi^{0}(\omega) d_i, \qquad i=1,2,3 \end{array}\right.$$ (2)

where $d_i$ is the dipole in the $i$-direction, $\chi_0$ is the susceptibility of the non-interacting Kohn-Sham system and $\Sigma$ the interaction kernel, cf. papers 1-3. The parameters of the method are:

solver_krylov

(integer): Maximum dimension of the Krylov space. This parameter is also called the restart parameter and it controls the amount of memory required by the matrix in the Krylov space.

Default: 20

solver_itermax

(integer): Maximum number of iterations to reach convergence.

Default: 100

solver_verbose

(integer): Controls output of information on convergence of the solver. If the value is non-zero, output is written in file fort.solver_verbose.

Default: 0

solver_eps

(real): tolerance for convergence.

Default: 0.001