Hi,
I see I am sorry, I misinterpreted the output -ts_adapt_monitor.
You are right point 2 is not an issue.
I there a way to let the time stepping continue with the last time step
instead of the initial time step?
Best Regards,
Moritz
Am 03.02.19 um 17:04 schrieb Zhang, Hong:
ex40 seems to work fine. Here is the output with -ts_monitor -ts_event_monitor
-ts_dt 0.01 :
8 TS dt 0.5 time 3.11
9 TS dt 0.5 time 3.61
TSEvent: iter 0 - Event 0 interval detected [3.61 - 4.11]
9 TS dt 0.467955 time 3.61 (r)
TSEvent: iter 1 - Stepping forward as no event detected in interval [3.61 -
4.07796]
10 TS dt 0.00365179 time 4.07796
TSEvent: iter 2 - Stepping forward as no event detected in interval [4.07796 -
4.08161]
11 TS dt 2.5403e-05 time 4.08161
TSEvent: Event 0 zero crossing at time 4.08163 located in 3 iterations
Ball hit the ground at t = 4.08 seconds
12 TS dt 0.0283673 time 4.08163
13 TS dt 0.01 time 4.11
14 TS dt 0.1 time 4.12
The event occurs during the step [3.61- 4.11]. After the event is located at
4.08163, the next step after the event should be 4.11-4.08163 = 0.02837 (see 12
TS) to complete the original step. After 4.11, the specified initial stepsize
dt=0.01 will be used.
Hong (Mr.)
On Feb 3, 2019, at 6:08 AM, Moritz Huck via petsc-users
<petsc-users@mcs.anl.gov> wrote:
Hi Barry,
src/ts/examples/tutorials/ex40.c (run with ARKIMEX3 and initial dt=1e-2) has
the same behavior:
TSEvent: iter 0 - Event 0 interval detected [3.61 - 4.11]
TSEvent: iter 1 - Stepping forward as no event detected in interval [3.61 -
4.07796]
TSEvent: iter 2 - Stepping forward as no event detected in interval [4.07796 -
4.08161]
TSEvent: Event 0 zero crossing at time 4.08163 located in 3 iterations
Ball hit the ground at t = 4.08 seconds
TSAdapt basic arkimex 0:3 step 13 accepted t=4.11 + 1.000e-02
dt=1.000e-01 wlte= 0 wltea= -1 wlter= -1
TSAdapt basic arkimex 0:3 step 14 accepted t=4.12 + 1.000e-01
dt=5.000e-01 wlte= 0 wltea= -1 wlter= -1
It continues at the end of the "event interval" with the initial timestep.
Best Regards,
Moritz
Am 03.02.19 um 02:43 schrieb Smith, Barry F.:
On Feb 2, 2019, at 12:08 PM, Moritz Huck via petsc-users
<petsc-users@mcs.anl.gov> wrote:
Hi,
I am trying to use SetEventHandler.
I hav eencountered two "problems":
1. after an event is encountered the next time step is needlessly small
(h=1e-6), even if a don't change anything in the function (for testing).
2. the integration does not continue at the event encounter
e.g. my eventfunction is g(t,u)=t-1,
the event is found in the step from t= 0.9 to 1.1 at tevent=1
but the next step is not 1+dt but it is 1.1 + dt
I would expect the next step to be 1.+dt
Hmm, this sounds like it could be an error. Could you send us a simple
code that exhibits it?
Thanks
Barry
Best Regards,
Moritz
