Stop and start from the last time step

ali_b124 · May 27, 2021, 04:08

Hello sir,

I want to stop a running simulation and start it after a while from the latest time step? Is that possible ?

Best regards.

kamath · May 27, 2021, 05:35

Hi Ali,
Yes, you can do that. But you also need to plan for this in advance.
This means, when you run your first simulation, use the P 40 and P41/ P42 options. This saves a state file in intervals specified by the commands above.

In order to continue the simulation, include I 40 /I 41 options. The simulation will load the previous state file selected using I 41 and continue from that point.

Be aware that files that print time series will be overwritten, so take care to save them separately before hot starting the second simulation.

ali_b124 · May 27, 2021, 09:19

Hi Arun,

Thanks for reply.

Best regards.

Bingcz · August 25, 2021, 06:48

Hello Sir,

I met a problem when I want to restart a simulation from the previous state file.

I have included P40 and P41, so I have state files, but when I include I40 and I41, then restart the case, the step and simtime are not right as shown in pictures attached. Could you please help about this?

Regards.
restart.jpg

save.jpg

Varada · August 19, 2023, 14:09

Hello REED3D team,

Is it necessary to use the same number of cores as before when reinitializing a simulation? I ran a simulation using 80 cores for a certain period. Later, I tried to restart the simulation using a state file, but this time with 40 cores and the command "I 40 1". However, I observed that the simulation started again from t=0.

Thank you.

kamath · August 20, 2023, 15:47

Not necessary. But you will have to provide an input (I 241) stating the start point.
Also afaik, the hot start option is currently under reconstruction, so it might be not working as needed.

Varada · August 21, 2023, 01:57

I conducted a 2D simulation focused on generating irregular waves without utilizing any structures. The simulation was carried out on my 12-core desktop system. The simulation runs smoothly when I pause it and then re-initialize. However, I encountered a contrasting situation when I attempted the same simulation on HPCE (High-Performance Computing Environment). In this case, the simulation starts from the initial time (t=0) whenever I re-initialize it.

I'm curious to understand the possible reasons behind this discrepancy in behavior between the desktop and HPCE runs.

Thank you in advance for your help.

May 27, 2021, 04:08	Stop and start from the last time step	#1
ali_b124 New Member Ali Burhan Join Date: Apr 2017 Location: İstanbul Posts: 13 Rep Power: 9	Hello sir, I want to stop a running simulation and start it after a while from the latest time step? Is that possible ? Best regards. fturkmen and Bingcz like this.

May 27, 2021, 05:35		#2
kamath Senior Member Arun Kamath Join Date: Nov 2014 Location: Trondheim, Norway Posts: 265 Rep Power: 14	Hi Ali, Yes, you can do that. But you also need to plan for this in advance. This means, when you run your first simulation, use the P 40 and P41/ P42 options. This saves a state file in intervals specified by the commands above. In order to continue the simulation, include I 40 /I 41 options. The simulation will load the previous state file selected using I 41 and continue from that point. Be aware that files that print time series will be overwritten, so take care to save them separately before hot starting the second simulation. __________________ Arun X years with REEF3D

August 25, 2021, 06:48	Restart problem	#4
Bingcz New Member Bingchang Zhang Join Date: Aug 2021 Posts: 9 Rep Power: 5	Hello Sir, I met a problem when I want to restart a simulation from the previous state file. I have included P40 and P41, so I have state files, but when I include I40 and I41, then restart the case, the step and simtime are not right as shown in pictures attached. Could you please help about this? Regards. restart.jpg save.jpg

August 20, 2023, 15:47		#6
kamath Senior Member Arun Kamath Join Date: Nov 2014 Location: Trondheim, Norway Posts: 265 Rep Power: 14	Not necessary. But you will have to provide an input (I 241) stating the start point. Also afaik, the hot start option is currently under reconstruction, so it might be not working as needed. __________________ Arun X years with REEF3D

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May 27, 2021, 09:19		#3
ali_b124 New Member Ali Burhan Join Date: Apr 2017 Location: İstanbul Posts: 13 Rep Power: 9	Hi Arun, Thanks for reply. Best regards.

August 19, 2023, 14:09		#5
Varada Member Bhargav Join Date: Aug 2022 Posts: 30 Rep Power: 4	Hello REED3D team, Is it necessary to use the same number of cores as before when reinitializing a simulation? I ran a simulation using 80 cores for a certain period. Later, I tried to restart the simulation using a state file, but this time with 40 cores and the command "I 40 1". However, I observed that the simulation started again from t=0. Thank you.

August 21, 2023, 01:57		#7
Varada Member Bhargav Join Date: Aug 2022 Posts: 30 Rep Power: 4	I conducted a 2D simulation focused on generating irregular waves without utilizing any structures. The simulation was carried out on my 12-core desktop system. The simulation runs smoothly when I pause it and then re-initialize. However, I encountered a contrasting situation when I attempted the same simulation on HPCE (High-Performance Computing Environment). In this case, the simulation starts from the initial time (t=0) whenever I re-initialize it. I'm curious to understand the possible reasons behind this discrepancy in behavior between the desktop and HPCE runs. Thank you in advance for your help.