>>> REDUCTION: max_red
By default, a TOUGH2 simulation stops if 20 consecutive time step reductions have occurred without convergence. This command changes the maximum number of allowable time step reductions to max_red. Time step reductions occur if:
(1) the initial time step is too large (see TOUGH2 variable DELTEN or DLT(1), and command >>> ADJUST);
(2) TOUGH2 parameter NOITE is too small;
(3) a failure in the EOS module occurs ;
(4) boundary conditions are changed drastically during the course of the simulation.
Variable max_red should only be increased to address problem (4), i.e., when drastic changes in generation rates (TOUGH2 block GENER) are imposed, or if Dirichlet boundary conditions are changed using command >> RESTART TIME or through subroutine USERBC.
>>> accept : 30 CONSECUTIVE time step reductions