1 #include <petsc/private/tsimpl.h> /*I "petscts.h" I*/
2
TSAdaptChoose_CFL(TSAdapt adapt,TS ts,PetscReal h,PetscInt * next_sc,PetscReal * next_h,PetscBool * accept,PetscReal * wlte,PetscReal * wltea,PetscReal * wlter)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;
8
9 PetscFunctionBegin;
10 PetscCall(TSGetCFLTime(ts, &cfltimestep));
11 PetscCall(TSAdaptCandidatesGet(adapt, &ncandidates, NULL, NULL, &ccflarray, NULL));
12 ccfl = (ncandidates > 0) ? ccflarray[0] : 1.0;
13
14 PetscCheck(adapt->always_accept, PetscObjectComm((PetscObject)adapt), PETSC_ERR_SUP, "Step rejection not implemented. The CFL implementation is incomplete/unusable");
15
16 /* Determine whether the step is accepted of rejected */
17 *accept = PETSC_TRUE;
18 if (h > cfltimestep * ccfl) {
19 if (adapt->always_accept) {
20 PetscCall(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));
21 } else {
22 PetscCall(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));
23 *accept = PETSC_FALSE;
24 }
25 }
26
27 /* The optimal new step based purely on CFL constraint for this step. */
28 hcfl = adapt->safety * cfltimestep * ccfl;
29 if (hcfl < adapt->dt_min) {
30 PetscCall(PetscInfo(adapt, "Cannot satisfy CFL constraint %g (with %g safety) at minimum time step %g with method coefficient %g, proceeding anyway\n", (double)cfltimestep, (double)adapt->safety, (double)adapt->dt_min, (double)ccfl));
31 }
32
33 *next_sc = 0;
34 *next_h = PetscClipInterval(hcfl, adapt->dt_min, adapt->dt_max);
35 *wlte = -1; /* Weighted local truncation error was not evaluated */
36 *wltea = -1; /* Weighted absolute local truncation error was not evaluated */
37 *wlter = -1; /* Weighted relative local truncation error was not evaluated */
38 PetscFunctionReturn(PETSC_SUCCESS);
39 }
40
41 /*MC
42 TSADAPTCFL - CFL adaptive controller for time stepping
43
44 Level: intermediate
45
46 .seealso: [](ch_ts), [](sec_ts_error_control), `TS`, `TSAdapt`, `TSGetAdapt()`, `TSAdaptType`
47 M*/
TSAdaptCreate_CFL(TSAdapt adapt)48 PETSC_EXTERN PetscErrorCode TSAdaptCreate_CFL(TSAdapt adapt)
49 {
50 PetscFunctionBegin;
51 adapt->ops->choose = TSAdaptChoose_CFL;
52 PetscFunctionReturn(PETSC_SUCCESS);
53 }
54