1 #include <petsc/private/tsimpl.h> /*I "petscts.h" I*/ 2 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 PetscReal hcfl, cfltimestep, ccfl; 5 PetscInt ncandidates; 6 const PetscReal *ccflarray; 7 8 PetscFunctionBegin; 9 PetscCall(TSGetCFLTime(ts, &cfltimestep)); 10 PetscCall(TSAdaptCandidatesGet(adapt, &ncandidates, NULL, NULL, &ccflarray, NULL)); 11 ccfl = (ncandidates > 0) ? ccflarray[0] : 1.0; 12 13 PetscCheck(adapt->always_accept, PetscObjectComm((PetscObject)adapt), PETSC_ERR_SUP, "Step rejection not implemented. The CFL implementation is incomplete/unusable"); 14 15 /* Determine whether the step is accepted of rejected */ 16 *accept = PETSC_TRUE; 17 if (h > cfltimestep * ccfl) { 18 if (adapt->always_accept) { 19 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)); 20 } else { 21 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)); 22 *accept = PETSC_FALSE; 23 } 24 } 25 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 PetscCall(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 } 31 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 PetscFunctionReturn(0); 38 } 39 40 /*MC 41 TSADAPTCFL - CFL adaptive controller for time stepping 42 43 Level: intermediate 44 45 .seealso: `TS`, `TSAdapt`, `TSGetAdapt()` 46 M*/ 47 PETSC_EXTERN PetscErrorCode TSAdaptCreate_CFL(TSAdapt adapt) { 48 PetscFunctionBegin; 49 adapt->ops->choose = TSAdaptChoose_CFL; 50 PetscFunctionReturn(0); 51 } 52