More info about Tick Length

[Shiva Shankaran]

Hi Harry,

I like to know much about Tick length - The length of the internal simulation steps.

The default value is 1 microsecond, if I change to different value the results are different.

Can you please give an explanation about it and what would be the preferable value?

Regards,

Shiva Shankaran 

[Harry King]

Shiva,

All the event times in the model are rounded internally to the nearest multiple of the TickLength value and saved as an integer value (actually, a 'long' in Java). This is necessary to avoid accumulated round-off error and the inconsistencies that result when floating point values are compared. Changing the TickLength input should not change model outputs as long as all the times are integer multiples of both TickLength values. Let me know if you find an example that violates this rule. As far as I know, everybody uses the default value for this input.

Harry

[Shiva Shankaran]

Harry,

Actually, am building a complex flow of model. Where multiple objects and materials are flowing simultaneously. Due to this one simulation takes hours to complete. Am also trying to run multiple scenarios where it leads days to complete the simulation. Increasing the tick length actually fasters the simulation but some % of different results. Any solution for this?

Shiva

[Harry King]

Shiva,

What value are you using for TickLength? How does this value compare to the small times steps you are using to model the flow of material?

Changing the TickLength input should not have any affect on execution speed or on the model results. The fact that your model is faster with a larger value for TickLength indicates that this value is too large and that you have introduced a systematic error. You should leave the TickLength input at its default value.

If you are trying to model the flow of material, you should consider using JaamSim Pro (jaamsimpro.com) which is designed for this type of model and is extremely fast. The cost to license the Pro version is comparable to Arena, Simio, etc. so this would have to be a paid modelling assignment. We are not providing a student version at this time.

Harry

[Shiva Shankaran]

Harry,

Yah I am actually using larger Tick Length as 1 sec. 

Will check with JaamSim Pro.

Thanks & Regards

Shiva