Actual source code: adaptcfl.c
1: #include <petsc/private/tsimpl.h>
3: static PetscErrorCode TSAdaptChoose_CFL(TSAdapt adapt, TS ts, PetscReal h, PetscInt *next_sc, PetscReal *next_h, PetscBool *accept, PetscReal *wlte, PetscReal *wltea, PetscReal *wlter)
4: {
5: PetscReal hcfl, cfltimestep, ccfl;
6: PetscInt ncandidates;
7: const PetscReal *ccflarray;
9: TSGetCFLTime(ts, &cfltimestep);
10: TSAdaptCandidatesGet(adapt, &ncandidates, NULL, NULL, &ccflarray, NULL);
11: ccfl = (ncandidates > 0) ? ccflarray[0] : 1.0;
15: /* Determine whether the step is accepted of rejected */
16: *accept = PETSC_TRUE;
17: if (h > cfltimestep * ccfl) {
18: if (adapt->always_accept) {
19: PetscInfo(adapt, "Step length %g with scheme of CFL coefficient %g did not satisfy user-provided CFL constraint %g, proceeding anyway\n", (double)h, (double)ccfl, (double)cfltimestep);
20: } else {
21: PetscInfo(adapt, "Step length %g with scheme of CFL coefficient %g did not satisfy user-provided CFL constraint %g, step REJECTED\n", (double)h, (double)ccfl, (double)cfltimestep);
22: *accept = PETSC_FALSE;
23: }
24: }
26: /* The optimal new step based purely on CFL constraint for this step. */
27: hcfl = adapt->safety * cfltimestep * ccfl;
28: if (hcfl < adapt->dt_min) {
29: PetscInfo(adapt, "Cannot satisfy CFL constraint %g (with %g safety) at minimum time step %g with method coefficient %g, proceding anyway\n", (double)cfltimestep, (double)adapt->safety, (double)adapt->dt_min, (double)ccfl);
30: }
32: *next_sc = 0;
33: *next_h = PetscClipInterval(hcfl, adapt->dt_min, adapt->dt_max);
34: *wlte = -1; /* Weighted local truncation error was not evaluated */
35: *wltea = -1; /* Weighted absolute local truncation error was not evaluated */
36: *wlter = -1; /* Weighted relative local truncation error was not evaluated */
37: return 0;
38: }
40: /*MC
41: TSADAPTCFL - CFL adaptive controller for time stepping
43: Level: intermediate
45: .seealso: [](chapter_ts), `TS`, `TSAdapt`, `TSGetAdapt()`, `TSAdaptType`
46: M*/
47: PETSC_EXTERN PetscErrorCode TSAdaptCreate_CFL(TSAdapt adapt)
48: {
49: adapt->ops->choose = TSAdaptChoose_CFL;
50: return 0;
51: }