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 { 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, proceding 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: [](chapter_ts), `TS`, `TSAdapt`, `TSGetAdapt()`, `TSAdaptType` 47 M*/ 48 PETSC_EXTERN PetscErrorCode TSAdaptCreate_CFL(TSAdapt adapt) 49 { 50 PetscFunctionBegin; 51 adapt->ops->choose = TSAdaptChoose_CFL; 52 PetscFunctionReturn(PETSC_SUCCESS); 53 } 54