1382     if (!ark->alg_is) {  in TSStep_ARKIMEX()
1383       PetscCall(TSARKIMEXComputeAlgebraicIS(ts, ts->ptime, Z, &ark->alg_is));  in TSStep_ARKIMEX()
1384       PetscCall(ISViewFromOptions(ark->alg_is, (PetscObject)ts, "-ts_arkimex_algebraic_is_view"));  in TSStep_ARKIMEX()
1389     if (ark->alg_is) PetscCall(VecISSet(Ydot0, ark->alg_is, 0.0));  in TSStep_ARKIMEX()
1772     PetscCall(ISDestroy(&ark->alg_is));  in TSReset_ARKIMEX()
1823 static PetscErrorCode TSARKIMEXComputeAlgebraicIS(TS ts, PetscReal time, Vec X, IS *alg_is)  in TSARKIMEXComputeAlgebraicIS()  argument
1852   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)dm), nz, nzr, PETSC_OWN_POINTER, alg_is));  in TSARKIMEXComputeAlgebraicIS()
1861 static PetscErrorCode TSARKIMEXGetAlgebraicIS(TS ts, DM dm, IS *alg_is)  in TSARKIMEXGetAlgebraicIS()  argument
1866 …!= ts->dm) PetscCall(PetscObjectQuery((PetscObject)dm, "TSARKIMEX_ALG_IS", (PetscObject *)alg_is));  in TSARKIMEXGetAlgebraicIS()
1867   else *alg_is = ax->alg_is;  in TSARKIMEXGetAlgebraicIS()
1877   IS          alg_is;  in SNESTSFormFunction_ARKIMEX()  local
1882   if (ark->scoeff == PETSC_MAX_REAL) PetscCall(TSARKIMEXGetAlgebraicIS(ts, dm, &alg_is));  in SNESTSFormFunction_ARKIMEX()
1889     if (!alg_is) {  in SNESTSFormFunction_ARKIMEX()
1891       PetscCall(TSARKIMEXComputeAlgebraicIS(ts, ark->stage_time, Z, &alg_is));  in SNESTSFormFunction_ARKIMEX()
1892       PetscCall(PetscObjectCompose((PetscObject)dm, "TSARKIMEX_ALG_IS", (PetscObject)alg_is));  in SNESTSFormFunction_ARKIMEX()
1893       PetscCall(PetscObjectDereference((PetscObject)alg_is));  in SNESTSFormFunction_ARKIMEX()
1894       PetscCall(ISViewFromOptions(alg_is, (PetscObject)snes, "-ts_arkimex_algebraic_is_view"));  in SNESTSFormFunction_ARKIMEX()
1897     PetscCall(VecISSet(F, alg_is, 0.0));  in SNESTSFormFunction_ARKIMEX()
1915   IS          alg_is;  in SNESTSFormJacobian_ARKIMEX()  local
1922   if (ark->scoeff == PETSC_MAX_REAL) PetscCall(TSARKIMEXGetAlgebraicIS(ts, dm, &alg_is));  in SNESTSFormJacobian_ARKIMEX()
1937       PetscCheck(alg_is, PetscObjectComm((PetscObject)dm), PETSC_ERR_PLIB, "Missing algebraic IS");  in SNESTSFormJacobian_ARKIMEX()
1940       PetscCall(MatZeroRowsIS(B, alg_is, 1.0, NULL, NULL));  in SNESTSFormJacobian_ARKIMEX()