1c4762a1bSJed Brown static char help[] = "Solves DAE with integrator only on non-algebraic terms \n"; 2c4762a1bSJed Brown 3c4762a1bSJed Brown #include <petscts.h> 4c4762a1bSJed Brown 5c4762a1bSJed Brown /* 6c4762a1bSJed Brown \dot{U} = f(U,V) 7c4762a1bSJed Brown F(U,V) = 0 8c4762a1bSJed Brown */ 9c4762a1bSJed Brown 10c4762a1bSJed Brown /* 11c4762a1bSJed Brown f(U,V) = U + V 12c4762a1bSJed Brown */ 13c4762a1bSJed Brown PetscErrorCode f(PetscReal t,Vec U,Vec V,Vec F) 14c4762a1bSJed Brown { 15c4762a1bSJed Brown PetscFunctionBeginUser; 169566063dSJacob Faibussowitsch PetscCall(VecWAXPY(F,1.0,U,V)); 17c4762a1bSJed Brown PetscFunctionReturn(0); 18c4762a1bSJed Brown } 19c4762a1bSJed Brown 20c4762a1bSJed Brown /* 21c4762a1bSJed Brown F(U,V) = U - V 22c4762a1bSJed Brown */ 23c4762a1bSJed Brown PetscErrorCode F(PetscReal t,Vec U,Vec V,Vec F) 24c4762a1bSJed Brown { 25c4762a1bSJed Brown PetscFunctionBeginUser; 269566063dSJacob Faibussowitsch PetscCall(VecWAXPY(F,-1.0,V,U)); 27c4762a1bSJed Brown PetscFunctionReturn(0); 28c4762a1bSJed Brown } 29c4762a1bSJed Brown 30c4762a1bSJed Brown typedef struct { 31c4762a1bSJed Brown PetscReal t; 32c4762a1bSJed Brown SNES snes; 33c4762a1bSJed Brown Vec U,V; 34c4762a1bSJed Brown PetscErrorCode (*f)(PetscReal,Vec,Vec,Vec); 35c4762a1bSJed Brown PetscErrorCode (*F)(PetscReal,Vec,Vec,Vec); 36c4762a1bSJed Brown } AppCtx; 37c4762a1bSJed Brown 38c4762a1bSJed Brown extern PetscErrorCode TSFunction(TS,PetscReal,Vec,Vec,void*); 39c4762a1bSJed Brown extern PetscErrorCode SNESFunction(SNES,Vec,Vec,void*); 40c4762a1bSJed Brown 41c4762a1bSJed Brown int main(int argc,char **argv) 42c4762a1bSJed Brown { 43c4762a1bSJed Brown AppCtx ctx; 44c4762a1bSJed Brown TS ts; 45c4762a1bSJed Brown Vec tsrhs,U; 46c4762a1bSJed Brown 47*327415f7SBarry Smith PetscFunctionBeginUser; 489566063dSJacob Faibussowitsch PetscCall(PetscInitialize(&argc,&argv,(char*)0,help)); 499566063dSJacob Faibussowitsch PetscCall(TSCreate(PETSC_COMM_WORLD,&ts)); 509566063dSJacob Faibussowitsch PetscCall(TSSetProblemType(ts,TS_NONLINEAR)); 519566063dSJacob Faibussowitsch PetscCall(TSSetType(ts,TSEULER)); 529566063dSJacob Faibussowitsch PetscCall(TSSetFromOptions(ts)); 539566063dSJacob Faibussowitsch PetscCall(VecCreateMPI(PETSC_COMM_WORLD,PETSC_DECIDE,1,&tsrhs)); 549566063dSJacob Faibussowitsch PetscCall(VecCreateMPI(PETSC_COMM_WORLD,PETSC_DECIDE,1,&U)); 559566063dSJacob Faibussowitsch PetscCall(TSSetRHSFunction(ts,tsrhs,TSFunction,&ctx)); 569566063dSJacob Faibussowitsch PetscCall(TSSetMaxTime(ts,1.0)); 57c4762a1bSJed Brown ctx.f = f; 58c4762a1bSJed Brown 599566063dSJacob Faibussowitsch PetscCall(SNESCreate(PETSC_COMM_WORLD,&ctx.snes)); 609566063dSJacob Faibussowitsch PetscCall(SNESSetFromOptions(ctx.snes)); 619566063dSJacob Faibussowitsch PetscCall(SNESSetFunction(ctx.snes,NULL,SNESFunction,&ctx)); 629566063dSJacob Faibussowitsch PetscCall(SNESSetJacobian(ctx.snes,NULL,NULL,SNESComputeJacobianDefault,&ctx)); 63c4762a1bSJed Brown ctx.F = F; 649566063dSJacob Faibussowitsch PetscCall(VecCreateMPI(PETSC_COMM_WORLD,PETSC_DECIDE,1,&ctx.V)); 65c4762a1bSJed Brown 669566063dSJacob Faibussowitsch PetscCall(VecSet(U,1.0)); 679566063dSJacob Faibussowitsch PetscCall(TSSolve(ts,U)); 68c4762a1bSJed Brown 699566063dSJacob Faibussowitsch PetscCall(VecDestroy(&ctx.V)); 709566063dSJacob Faibussowitsch PetscCall(VecDestroy(&tsrhs)); 719566063dSJacob Faibussowitsch PetscCall(VecDestroy(&U)); 729566063dSJacob Faibussowitsch PetscCall(SNESDestroy(&ctx.snes)); 739566063dSJacob Faibussowitsch PetscCall(TSDestroy(&ts)); 749566063dSJacob Faibussowitsch PetscCall(PetscFinalize()); 75b122ec5aSJacob Faibussowitsch return 0; 76c4762a1bSJed Brown } 77c4762a1bSJed Brown 78c4762a1bSJed Brown /* 79c4762a1bSJed Brown Defines the RHS function that is passed to the time-integrator. 80c4762a1bSJed Brown 81c4762a1bSJed Brown Solves F(U,V) for V and then computes f(U,V) 82c4762a1bSJed Brown */ 83c4762a1bSJed Brown PetscErrorCode TSFunction(TS ts,PetscReal t,Vec U,Vec F,void *actx) 84c4762a1bSJed Brown { 85c4762a1bSJed Brown AppCtx *ctx = (AppCtx*)actx; 86c4762a1bSJed Brown 87c4762a1bSJed Brown PetscFunctionBeginUser; 88c4762a1bSJed Brown ctx->t = t; 89c4762a1bSJed Brown ctx->U = U; 909566063dSJacob Faibussowitsch PetscCall(SNESSolve(ctx->snes,NULL,ctx->V)); 919566063dSJacob Faibussowitsch PetscCall((*ctx->f)(t,U,ctx->V,F)); 92c4762a1bSJed Brown PetscFunctionReturn(0); 93c4762a1bSJed Brown } 94c4762a1bSJed Brown 95c4762a1bSJed Brown /* 96c4762a1bSJed Brown Defines the nonlinear function that is passed to the nonlinear solver 97c4762a1bSJed Brown */ 98c4762a1bSJed Brown PetscErrorCode SNESFunction(SNES snes,Vec V,Vec F,void *actx) 99c4762a1bSJed Brown { 100c4762a1bSJed Brown AppCtx *ctx = (AppCtx*)actx; 101c4762a1bSJed Brown 102c4762a1bSJed Brown PetscFunctionBeginUser; 1039566063dSJacob Faibussowitsch PetscCall((*ctx->F)(ctx->t,ctx->U,V,F)); 104c4762a1bSJed Brown PetscFunctionReturn(0); 105c4762a1bSJed Brown } 106c4762a1bSJed Brown 107303a5415SBarry Smith /*TEST 108c4762a1bSJed Brown 109303a5415SBarry Smith test: 110303a5415SBarry Smith args: -ts_monitor -ts_view 111303a5415SBarry Smith 112303a5415SBarry Smith TEST*/ 113