ERROR: Memory allocation failed for WALL in the routine INIT

[ivory]

Hi Everyone!

i have been working on getting a purely FDS computer set up and it was
going great until i have come across this error:

ERROR: Memory allocation failed for WALL in the routine INIT

The file is a large stadium approx 28,800,000 cells (created on
pyrosim V4 and converted to pyrosim V5). i have tried scaling up the
grid sizing and it still comes up with the same error. im just a
little unsure what the error is trying to direct me to... does the
computer not have enough processing power to run this size simulation?
(as this is a new pc i have not yet tested the boundaries so to
speak)

i have previously run this model with FDS4 (pyrosim V4) on a smaller
scale and not had any problems...

Any help on this matter would be greatly appreciated :D

Regards

Ivory

[Glenn Forney]

I would say your computer does not have enough memory.

Start with a simple plume fire in an open box Then up the number of
grid cells in the x, , y and z directions noting the number of grid
cells each time. Meanwhile open up the task manager by typing
<CTRL><ALT><DELELTE> to see how much memory your computer has and is
using. Bump up the number of grid cells until FDS fails. This will
bgive you a rough idea of how many grid cells you may simulate on your
computer.

--
Glenn Forney
National Institute of Standards and Technology
100 Bureau Drive, Stop 8663
Gaithersburg MD 20899-8663

Telephone: (301) 975 2313
FAX: (301) 975 4052

Pre-decisional and sensitive information. Not for attribution, distribution, or reproduction.

[Kevin]

You need to run this case with the parallel version of FDS on multiple
computers. You need roughly 1 GB RAM per million cells.

[Dave McGill]

Hi Ivory,

A ball-park guide is that you need about a GB of memory for every
million cells, which would put your memory requirements in the range
of 30 GB. If this is a single PC, I'm guessing you have a maximum of 4
GB.

It can get more complicated with PyroSim If your model contains angled
or curved walls. PyroSim represents these by tens of thousands of OBST
lines. (How many lines are in the .fds file?) This results in a
greater need for memory when FDS begins, so you might need 60 GB of
memory to handle the start-up activities and then 30 GB to run the
model.

It gets worse. If you were able to have enough memory to get the job
up and running, or simplifed you model to fit within the memory you
have, it would take months to solve on one PC. For jobs that big, the
only solution is to use multi-processing; say 30 processors.

I hope that helps.

Dave