2774     IS              isx, isv, istmp;  in SetProblem()  local
2789     PetscCall(ISCreateBlock(PETSC_COMM_WORLD, dim, Np, idx, PETSC_COPY_VALUES, &isv));  in SetProblem()
2793     PetscCall(TSRHSSplitSetIS(ts, "momentum", isv));  in SetProblem()
2795     PetscCall(ISDestroy(&isv));  in SetProblem()
2872   IS       isx, isv;  in InitializeSolveAndSwarm()  local
2895   PetscCall(TSRHSSplitGetIS(ts, "momentum", &isv));  in InitializeSolveAndSwarm()
2899   PetscCall(VecISCopy(u, isv, SCATTER_FORWARD, gv));  in InitializeSolveAndSwarm()
2925     IS         isx, isv;  in MigrateParticles()  local
2930     PetscCall(TSRHSSplitGetIS(ts, "momentum", &isv));  in MigrateParticles()
2932     PetscCall(VecGetSubVector(u, isv, &momentum));  in MigrateParticles()
2938     PetscCall(VecISCopy(u, isv, SCATTER_REVERSE, gv));  in MigrateParticles()
2971     PetscCall(VecRestoreSubVector(u, isv, &momentum));  in MigrateParticles()