1 static char help[] ="Tests TS time span \n\n"; 2 3 #include <petscts.h> 4 5 static PetscErrorCode RHSFunction(TS ts,PetscReal t,Vec X,Vec F,void *ctx) 6 { 7 PetscInt i,n; 8 const PetscScalar *xx; 9 /* */ PetscScalar *ff; 10 11 PetscFunctionBegin; 12 PetscCall(VecGetLocalSize(X,&n)); 13 PetscCall(VecGetArrayRead(X,&xx)); 14 PetscCall(VecGetArray(F,&ff)); 15 if (n >= 1) ff[0] = 1; 16 for (i = 1; i < n; i++) ff[i] = (i+1)*(xx[i-1]+PetscPowReal(t,i))/2; 17 PetscCall(VecRestoreArrayRead(X,&xx)); 18 PetscCall(VecRestoreArray(F,&ff)); 19 PetscFunctionReturn(0); 20 } 21 22 int main(int argc, char *argv[]) 23 { 24 TS ts; 25 Vec X,*Xs; 26 PetscInt i,n,N = 9; 27 PetscReal tspan[3] = {0, 0.5, 1.0}; 28 const PetscReal *tspan2; 29 30 PetscCall(PetscInitialize(&argc,&argv,NULL,help)); 31 PetscCall(TSCreate(PETSC_COMM_SELF,&ts)); 32 PetscCall(TSSetType(ts,TSRK)); 33 PetscCall(TSSetRHSFunction(ts,NULL,RHSFunction,NULL)); 34 PetscCall(VecCreateSeq(PETSC_COMM_SELF,N,&X)); 35 PetscCall(VecZeroEntries(X)); 36 PetscCall(TSSetTimeSpan(ts,3,tspan)); 37 PetscCall(TSSetExactFinalTime(ts,TS_EXACTFINALTIME_MATCHSTEP)); 38 PetscCall(TSSetFromOptions(ts)); 39 PetscCall(TSSolve(ts,X)); 40 PetscCall(TSGetTimeSpanSolutions(ts,&n,&Xs)); 41 PetscCall(TSGetTimeSpan(ts,&n,&tspan2)); 42 PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Time Span: ")); 43 for (i=0; i<n; i++) PetscCall(PetscPrintf(PETSC_COMM_WORLD," %g",(double)tspan2[i])); 44 PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n")); 45 PetscCall(TSDestroy(&ts)); 46 PetscCall(VecDestroy(&X)); 47 PetscCall(PetscFinalize()); 48 return 0; 49 } 50 51 /*TEST 52 53 testset: 54 test: 55 suffix: 1 56 args: -ts_monitor 57 test: 58 suffix: 2 59 args: -ts_monitor -ts_time_span 0,0.3,0.6,1.0 60 TEST*/ 61