[petsc-users] Some clarifications about TS ex3.c

[Sajid Ali]

Another question I want to ask is about dttol that is used in the Monitor
function as follows :

417:   dttol = .0001;
418:   PetscOptionsGetReal(NULL,NULL,"-dttol",&dttol,NULL);
419:   if (dt < dttol) {
420:     dt  *= .999;
421:     TSSetTimeStep(ts,dt);
422:   }

Is this decreasing dt if it's less than tolerance ?

I commented out the norm calculation (lines 404-415) the time is stuck at 0
( as per the output of -ts_monitor). But if I comment out the above lines
(417-422) as well, everything works fine. What explains this behaviour ?

Thank You!
Sajid Ali
Applied Physics
Northwestern University
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