1af0996ceSBarry Smith #include <petsc/private/tsimpl.h> /*I "petscts.h" I*/ 28d59e960SJed Brown 38d59e960SJed Brown typedef struct { 41566a47fSLisandro Dalcin PetscReal safety; /* safety factor relative to target CFL constraint */ 58d59e960SJed Brown } TSAdapt_CFL; 68d59e960SJed Brown 75e4ed32fSEmil Constantinescu static PetscErrorCode TSAdaptChoose_CFL(TSAdapt adapt,TS ts,PetscReal h,PetscInt *next_sc,PetscReal *next_h,PetscBool *accept,PetscReal *wlte,PetscReal *wltea,PetscReal *wlter) 88d59e960SJed Brown { 98d59e960SJed Brown TSAdapt_CFL *cfl = (TSAdapt_CFL*)adapt->data; 108d59e960SJed Brown PetscErrorCode ierr; 111566a47fSLisandro Dalcin PetscReal hcfl,cfltimestep,ccfl; 121566a47fSLisandro Dalcin PetscInt ncandidates; 131566a47fSLisandro Dalcin const PetscReal *ccflarray; 148d59e960SJed Brown 158d59e960SJed Brown PetscFunctionBegin; 161566a47fSLisandro Dalcin ierr = TSGetCFLTime(ts,&cfltimestep);CHKERRQ(ierr); 171566a47fSLisandro Dalcin ierr = TSAdaptCandidatesGet(adapt,&ncandidates,NULL,NULL,&ccflarray,NULL);CHKERRQ(ierr); 181566a47fSLisandro Dalcin ccfl = (ncandidates > 0) ? ccflarray[0] : 1.0; 198d59e960SJed Brown 201566a47fSLisandro Dalcin /* Determine whether the step is accepted of rejected */ 211566a47fSLisandro Dalcin *accept = PETSC_TRUE; 221566a47fSLisandro Dalcin if (h > cfltimestep * ccfl) { 23*bf997491SLisandro Dalcin if (adapt->always_accept) { 241566a47fSLisandro Dalcin ierr = PetscInfo3(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);CHKERRQ(ierr); 258d59e960SJed Brown } else { 261566a47fSLisandro Dalcin ierr = PetscInfo3(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);CHKERRQ(ierr); 278d59e960SJed Brown *accept = PETSC_FALSE; 288d59e960SJed Brown } 298d59e960SJed Brown } 308d59e960SJed Brown 311566a47fSLisandro Dalcin /* The optimal new step based purely on CFL constraint for this step. */ 321566a47fSLisandro Dalcin hcfl = cfl->safety * cfltimestep * ccfl; 331566a47fSLisandro Dalcin if (hcfl < adapt->dt_min) { 341566a47fSLisandro Dalcin ierr = PetscInfo4(adapt,"Cannot satisfy CFL constraint %g (with %g safety) at minimum time step %g with method coefficient %g, proceding anyway\n",(double)cfltimestep,(double)cfl->safety,(double)adapt->dt_min,(double)ccfl);CHKERRQ(ierr); 351566a47fSLisandro Dalcin } 361566a47fSLisandro Dalcin 378d59e960SJed Brown *next_sc = 0; 388d59e960SJed Brown *next_h = PetscClipInterval(hcfl,adapt->dt_min,adapt->dt_max); 390b99f514SJed Brown *wlte = -1; /* Weighted local truncation error was not evaluated */ 405e4ed32fSEmil Constantinescu *wltea = -1; /* Weighted absolute local truncation error was not evaluated */ 415e4ed32fSEmil Constantinescu *wlter = -1; /* Weighted relative local truncation error was not evaluated */ 428d59e960SJed Brown PetscFunctionReturn(0); 438d59e960SJed Brown } 448d59e960SJed Brown 458d59e960SJed Brown static PetscErrorCode TSAdaptDestroy_CFL(TSAdapt adapt) 468d59e960SJed Brown { 478d59e960SJed Brown PetscErrorCode ierr; 488d59e960SJed Brown 498d59e960SJed Brown PetscFunctionBegin; 508d59e960SJed Brown ierr = PetscFree(adapt->data);CHKERRQ(ierr); 518d59e960SJed Brown PetscFunctionReturn(0); 528d59e960SJed Brown } 538d59e960SJed Brown 544416b707SBarry Smith static PetscErrorCode TSAdaptSetFromOptions_CFL(PetscOptionItems *PetscOptionsObject,TSAdapt adapt) 558d59e960SJed Brown { 568d59e960SJed Brown TSAdapt_CFL *cfl = (TSAdapt_CFL*)adapt->data; 578d59e960SJed Brown PetscErrorCode ierr; 588d59e960SJed Brown 598d59e960SJed Brown PetscFunctionBegin; 60e55864a3SBarry Smith ierr = PetscOptionsHead(PetscOptionsObject,"CFL adaptive controller options");CHKERRQ(ierr); 611566a47fSLisandro Dalcin ierr = PetscOptionsReal("-ts_adapt_cfl_safety","Safety factor relative to target CFL constraint","",cfl->safety,&cfl->safety,NULL);CHKERRQ(ierr); 62c524d1a0SJed Brown /* The TS implementations do not currently communicate CFL information to the controller. There is a placeholder, but 63c524d1a0SJed Brown * we do not believe it to provide sufficiently rich information. That means the CFL adaptor is incomplete and 64c524d1a0SJed Brown * unusable. Do not delete the guard below unless you have finished the implementation. */ 65*bf997491SLisandro Dalcin if (!adapt->always_accept) SETERRQ(PetscObjectComm((PetscObject)adapt),PETSC_ERR_SUP,"Step rejection not implemented. The CFL implementation is incomplete/unusable"); 668d59e960SJed Brown ierr = PetscOptionsTail();CHKERRQ(ierr); 678d59e960SJed Brown PetscFunctionReturn(0); 688d59e960SJed Brown } 698d59e960SJed Brown 708d59e960SJed Brown /*MC 718d59e960SJed Brown TSADAPTCFL - CFL adaptive controller for time stepping 728d59e960SJed Brown 738d59e960SJed Brown Level: intermediate 748d59e960SJed Brown 758d59e960SJed Brown .seealso: TS, TSAdapt, TSSetAdapt() 768d59e960SJed Brown M*/ 778cc058d9SJed Brown PETSC_EXTERN PetscErrorCode TSAdaptCreate_CFL(TSAdapt adapt) 788d59e960SJed Brown { 798d59e960SJed Brown PetscErrorCode ierr; 808d59e960SJed Brown TSAdapt_CFL *a; 818d59e960SJed Brown 828d59e960SJed Brown PetscFunctionBegin; 83b00a9115SJed Brown ierr = PetscNewLog(adapt,&a);CHKERRQ(ierr); 848d59e960SJed Brown adapt->data = (void*)a; 851566a47fSLisandro Dalcin 868d59e960SJed Brown adapt->ops->choose = TSAdaptChoose_CFL; 878d59e960SJed Brown adapt->ops->setfromoptions = TSAdaptSetFromOptions_CFL; 888d59e960SJed Brown adapt->ops->destroy = TSAdaptDestroy_CFL; 898d59e960SJed Brown 908d59e960SJed Brown a->safety = 0.9; 918d59e960SJed Brown PetscFunctionReturn(0); 928d59e960SJed Brown } 93