211   PetscReal             ptime, next_time_step = ts->time_step;  in TSStep_BasicSymplectic()  local
218   PetscCall(TSGetTime(ts, &ptime));  in TSStep_BasicSymplectic()
219   PetscCall(TSSetTime(subts_p, ptime));  in TSStep_BasicSymplectic()
220   PetscCall(TSSetTime(subts_q, ptime));  in TSStep_BasicSymplectic()
224     PetscCall(TSPreStage(ts, ptime));  in TSStep_BasicSymplectic()
229       PetscCall(TSComputeRHSFunction(subts_q, ptime, p, q_update));  in TSStep_BasicSymplectic()
234       ptime = ptime + scheme->d[iter] * ts->time_step;  in TSStep_BasicSymplectic()
235       PetscCall(TSComputeRHSFunction(subts_p, ptime, q, p_update));  in TSStep_BasicSymplectic()
240     PetscCall(TSPostStage(ts, ptime, 0, &solution));  in TSStep_BasicSymplectic()
241     PetscCall(TSAdaptCheckStage(ts->adapt, ts, ptime, solution, &stageok));  in TSStep_BasicSymplectic()
243     PetscCall(TSFunctionDomainError(ts, ptime, solution, &stageok));  in TSStep_BasicSymplectic()
249   else ts->ptime += next_time_step;  in TSStep_BasicSymplectic()
350   PetscReal           alpha  = (ts->ptime - t) / ts->time_step;  in TSInterpolate_BasicSymplectic()