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1

Pathfinder / Occupants move very slowly on the stairs with Plot3d

« on: January 14, 2022, 10:22:44 am »

Hi,
We have a coupled simulation with Plot3D file. We selected the option that the occupants move slower in smoke. Everything works and loads as it should. But the occupants move very slowly on the stairs and ramps, like 0.1 m/s. As soon as they are away from these then they start moving quickly again. We don't have any smoke or reduced visibility on the stairs. Without the option to move slower in smoke they move much faster.
any ideas? Thanks, Robin

2

PyroSim / Results crashing problem

« on: November 10, 2021, 02:47:18 am »

Hi.

I had a file that crashed upon opening in Pyrosim Results, so I tried it in smokeview and it crashed when I opened the particles file. I saw this post here
https://groups.google.com/g/fds-smv/c/v3l2zw2FddQ
So I installed latest version of smokeview and now I can open the particles in smokeview. Still does not work in Pyrosim. Is this a known bug, any workarounds, or will it be fixed soon? is it possible to force results not to open the particles when it starts?

3

Pathfinder / Ryzen compatibility. Minimum graphic card capability.

« on: November 05, 2021, 07:31:34 am »

Hi. Does anyone have anyone experience with Pathfinder on a Ryzen system? We need a new PC to run Pathfinder/Pyrosim and I am interested in Ryzen. We have a cluster for big FDS simulations, but it would be good if we could do small or tests runs on the front-end Ryzen system.

Also, can anyone tell me what would be a minimum graphic capability. The other people in the office seem to think we need a super high-end graphics card for pathfinder, I imagine a low-end graphic card will do, possibly even the on-board graphics, but I don't want to risk being wrong.

4

PyroSim / Automatic FED Slice

« on: September 02, 2021, 02:59:04 am »

In Smokeview it creates an FED 2D slice automatically at 11.25m when I add the following lines:

&SLCF QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON DIOXIDE', PBZ=11.25/
&SLCF QUANTITY='VOLUME FRACTION', SPEC_ID='CARBON MONOXIDE', PBZ=11.25/
&SLCF QUANTITY='VOLUME FRACTION', SPEC_ID='OXYGEN', PBZ=11.25/

Apparently smokeview calculates this. But I did some tests and it seems like this is not possible in Pyrosim results. Is this correct?

Thanks.

5

PyroSim / Hardware requirements for Pyrosim only (not simulation), Laptop

« on: February 01, 2021, 04:37:45 am »

Hi.

I am considering running Pyrosim (but not the actual FDS simulation) on a Laptop, can you give me some hardware requirements? The simulation will run on remotely on another machine.

OR can anyone give me some examples where Pyrosim is installed and runs smoothly on a laptop/lower power machine.

Thanks.

6

PyroSim / CPU Usage graphs

« on: February 12, 2020, 03:01:30 am »

Hi.

I am new to Pyrosim, I was expecting there to be a function that would give me some feedback on CPU usage so I accurately predict how long the simulation would take (and optimise). Is there something like this? For example:
-A graph of seconds simulated per step/wall clock time per step.
-A breakdown of what % of the time is spent in each routine as the simulation progresses. i.e. what percentage of the simulation is in PART/COMM/FIRE etc, perhaps every 30 seconds or so. so I can see where to optimise.

I think this would be really useful, for example, before I used Pyrosim I would look at the cpu.csv with excel and I noticed that all my runs were going half the speed from Friday night to Monday morning. My sims were running on Windows computers that I would access with RDP and when I shut down the RDP session the simulations would still run, but because they were not in console mode (but effectively in the log in screen mode) windows would slow down the CPUs. It was so much easier to diagnose this when you have a graph of simulation speed against simulation time. Same goes for  PART slowdown when I am doing a sprinkler simulation, way easier to see with a  graph.

I suppose I could just make a standard excel file to do this, but I just want to see if Pyrosim has it built in first.

7

PyroSim / disable MPI if simulating only with openPM

« on: September 04, 2019, 03:50:05 am »

Hi. I hope this is a simple question. I am new to FDS.

So a colleague of mine has left and has handed me some simulations that have already taken months and have months more to go. The meshes were not divided up, it is just one huge mesh. It is an eight core machine, with 1 MPI process and 6 openMP threads. I just turned off hyper-threading and restarted.

So as I understand it, there is no point in using MPI, so is there an advantage to disabling it (if that is possible)? and only use OpenPM.

To be honest, I am a bit confused, if I have 1 MPI process, does that mean that the simulation is running on just one core? As the PC has one core constantly at 100%. whilst the other cores, are jumping between 10 and ~90% (but all 7 cores, not just the other 5, also confusing) .  So I am not even sure if the OpenMP is using all 6 cores, or if MPI has forced it on to a single core.

Thanks, I hope that is clear,
Rob