> On Jul 26, 2017, at 9:31 AM, Lisandro Dalcin <[email protected]> wrote:
> 
> On 26 July 2017 at 16:34, Stefano Zampini <[email protected]> wrote:
>> 
>> We should come to an agreement on it, as it is used to monitoring a TSSolve
>> call, and to save the trajectory, as per commit
>> 
> 
> WTF??? Who changed the calls to TSMonitor() to use ts->total_steps ?
> What's the rationale? So now I get this output with two successive
> {TSSetTime(ts,0); TSSolve(ts,NULL)} calls using -ts_monitor
> -ts_max_steps 3:
> 
> 0 TS dt 0.005 time 0.
> 1 TS dt 0.00623684 time 0.005
> 2 TS dt 0.00630727 time 0.0112368
> 3 TS dt 0.00638241 time 0.0175441
> 3 TS dt 0.00638241 time 0.
> 4 TS dt 0.00814772 time 0.00638241
> 5 TS dt 0.00772423 time 0.0145301
> 6 TS dt 0.00706187 time 0.0222544
> 
> Barry, what should be the behavior of two successive TSSolve() calls?
> Should the ts->step counter be reset to 0 or not? Otherwise, we should
> we need a ts->init_time to set ts->ptime=ts->init_time before starting
> to step.
> 
> So, in short there are two possible behaviors:
> 
> 1) A second (and third, and so on) TSSolve() continues from the place
> the previous solve stoped, the ts->step counter is not reset, the
> ts->steprestart for multistep methods (and FSAL property in RK) is not
> reset (and probably not reset ksp/snes iteration counters).
> 
> 2) A TSSolve() start always fresh, the initial time and time step are
> restored from values stashed int the TS structure, all counters are
> reset, and so on, whatever is needed
> 
> Barry, as our benevolent dictator for life, could you please rule on
> this? Maybe the first behavior I mentioned is the right one, but if we
> go for it, we should provide some API to support the second case (eg,
> TSRestart()).

Yes, when we do two consecutive TSSolve(), the first behavior is expected, 
except that TSSolve() resets ts->steps, not ts->total_steps.

For the second case, I agree we need some better API because TSReset() resets 
everything but sometimes we need to reset just the step counters.

Hong

> 
> As usual after a complaint, I volunteer to implement any required change.
> 
> 
> 
> 
> -- 
> Lisandro Dalcin
> ============
> Research Scientist
> Computer, Electrical and Mathematical Sciences & Engineering (CEMSE)
> Extreme Computing Research Center (ECRC)
> King Abdullah University of Science and Technology (KAUST)
> http://ecrc.kaust.edu.sa/
> 
> 4700 King Abdullah University of Science and Technology
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> 
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