The user first creates a TS object with the command
ierr = int TSCreate(MPI_Comm comm,TSProblemType problemtype,TS *ts);The TSProblemType is one of TS_LINEAR or TS_NONLINEAR, to indicate whether F(u,t) is given by a matrix A, or A(t), or a function F(u,t).
One can set the solution method with the routine
ierr = TSSetType(TS ts,TSType type);Currently supported types are TS_EULER, TS_BEULER, and TS_PSEUDO or the command line option -ts_type euler, beuler, pseudo.
Set the initial time and timestep with the command
ierr = TSSetInitialTimeStep(TS ts,double time,double dt);One can change the timestep with the command
ierr = TSSetTimeStep(TS ts,double dt);One can determine the current timestep with the routine
ierr = TSGetTimeStep(TS ts,double* dt);Here, ``current'' refers to the timestep being used to attempt to promote the solution form un to un+1.
One sets the total number of timesteps to run or the total time to run
(whatever is first) with the command
ierr = TSSetDuration(TS ts,int maxsteps,double maxtime);One sets up the timestep context with
ierr = TSSetUp(TS ts);destroys it with
ierr = TSDestroy(TS ts);and views it with
ierr = TSView(TS ts,Viewer viewer);