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64CHAPTER 6. DRIFT-DIFFUSION SIMULATION OF ELECTRONS AND HOLES
also not too small to minimize the number of iterations. Values between 1 and 10 should
be a good choice.
The nonlin_step_tol defines at which line search step size (in l2 -norm) the algorithm
stops, i.e. assumes to have reached convergence. nonlin_step_tol is measured in eV.
6.5.2
Parameters for the TIBERCAD nonlinear solver
Table 6.14 summarizes the parameters used for the TIBERCAD implementation of the
line search algorithm.
keyword
nonlin_rel_tol
nonlin_abs_tol
nonlin_step_tol
nonlin_max_it
description
relative tolerance for the residual l2 -norm
(with respect to first nonlinear step)
absolute tolerance for the residual l2 -norm
tolerance for the maximum norm of the nonlinear step (eV)
maximum number of nonlinear iterations
default
10e-9
10e-15
10e-3
20
Table 6.14: Parameters for the TIBERCAD line search
The stopping criterion based on the line search step uses the maximum norm of the
nonlinear step, i.e. convergence is controlled locally. In addition to the parameters in
table 6.14 one has to provide also parameters for the linear solver.
6.5.3
Parameters for the PARDISO linear solver
NOTE: the PARDISO linear solver is currently not included in the distribution.
Currently the PARDISO interface has no adjustable parameters.