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Different simulation results on different PC's

Solution Partner Legend Solution Partner Legend
Solution Partner Legend

Hi,

 

I have encountered something I cannot wrap my head around. Either it's me doing something wrong or misunderstanding how something works, or it may be a problem with Plant Simulation I haven't seen anyone encounter yet.

 

I recently had a situation in Plant Simulation where 5 computers were involved. The specifications of the computers was as follows. The differences are marked in bold. The manufacturer of the SSD's and RAM was different but I figured this shouldn't play a role anyway, so they are shown as the "same".

 

Computer 1

  • Plant Simulation Version: 13.2 Full Version DVD (as downloaded through GTAC's download page)
    • Specific version (seen in Help -> About): 13.2.0.1077
  • OS: Windows 7 SP1 64-bit
  • CPU: Type A
  • RAM: 16GB
  • HDD: SSD

Computer 2, 3, 4 = same Plant Simulation installation media, same OS, CPU, RAM and SSD (the computers are identical)

 

Computer 5:

  • Plant Simulation Version: 13.2 (same installation media as PC's 1-4)
    • Specific version (seen in Help -> About): 13.2.0.1077
  • OS: Windows 10 Pro 64-bit
  • CPU: Type B
  • RAM: 16GB
  • HDD: SSD

 

 

I now have access to Computer 1 and Computer 5 in a controlled environment to show what I mean in the screenshots below. The only difference between the computers should be the hardware and OS. The simulation models should be exactly the same, per the windows I have opened in the model files to verify that. We can also see that the predecessors and successors are exactly the same in both models, so the objects are connected in the same order.

 

The models were built individually, so I didn't create the .spp on computer 1 then copy it to computer 5. Computer 1 made the model from scratch, and so did computer 5.

 

As you can see, the output of the model is not the same. In fact it differs by quite a lot (841 vs 906), despite using the exact same object settings and same plant simulation version. Only the hardware and OS is different.

 

2017-06-12 09_18_29-utb1 - TeamViewer.pngModel output: Windows 7 Pro SP1 64-bit

2017-06-12 09_25_24-.pngModel Output: Windows 10 Pro 64-bit

As an additional example, I tried running both Plant Simulation v13.1 and 13.2 side by side on Computer 5 and also got varying output despite using the same object settings:

 

2017-06-12 09_57_06-NoName.spp - Tecnomatix Plant Simulation 13.2 - [.Models.Frame].pngLeft: PS 13.1, Right: PS 13.2 

 

 

Is there something I am doing wrong or shouldn't the output of both models be exactly the same?

 

They are built in the exact same workflow sequence

  1. Create folder in Class Library -> Name it "MyObjects"
  2. Duplicate "SingleProc" from "Material Flow" folder in Class Library, move it to "MyObjects" and name it "SP1"
  3. Use "Source" from "Material Flow" Class Library, drag it into the frame
  4. Drag "SP1" from "MyObjects" to frame, continue placing the SP1's and renaming them according to the screenshot (5 total)
  5. Connect them in this order
    1. Source -> SP1
    2. SP1 -> SP2
    3. SP2 -> SP3
    4. SP1 -> SP4
    5. SP4 -> SP5
  6. Use "Drain" from "Material Flow" Class Library and drag it into the frame
  7. Connect SP5 -> Drain
  8. Add "DisplayPanel" from Class Library
  9. Drag "Drain" onto "DisplayPanel", change text size to Extra Large
  10. Double Click "SP1" in "MyObjects" and add a failure with these parameters, the rest being default:
    1. Availablity: 80%
    2. MTTR: 8:00
  11. Open EventController
    1. RandomNumbersVariant = 3
    2. Simulation End: 1:00:00:00 (1 day)
  12. Run the simulation
  13. Check DisplayPanel

 

It is not the most complex model, but I would expect that in this scenario, the output should be the same regardless of which PC we are using, but it is not.

 

I cannot figure out why this is! The varying output also occurred between PC's 1-4 (the identical ones), but since this may have been down to user error I tested this myself in a controlled environment which is the result of the screenshots.

 

Any ideas?

 

 

1 REPLY

Re: Different simulation results on different PC's

Siemens Phenom Siemens Phenom
Siemens Phenom

Hello,

your model contains objects with failure, such that the behavior of your model depends on the attribute Randomseed of the used objects. The assignments of these values depends on the sequence of insertion.

Please use the AttributExplorer and consider the values of the attribute Randomseed. As you mentioned also the sequence of insertion of the connectors influenced the results which is also the case in a non-stochastic simulations.

Your expectation is correct that the results must be equal on different computers. Therefore I recommend to compare the results of the same spp file on different computers.

Regards,

Peter