Error: out of memory in MCXlab

[ALEXANDER P. Dumont]

Hi Dr. Fang

When I run my simulations with mcxlab, I get a weird error:

MCXLAB ERROR -2 in unit mcx_core.cu:1090

Error: out of memory

I have attached my script., but it uses an order of magnitude less photons than the limit, so I do not really understand why i am getting this errror. Also, my system currently has 32 gb of ram so I do not think it can be from that. 

[Qianqian Fang]

since the complain happens inside mcx_core.cu, so, mcxlab
was likely complaining about GPU memory, not the host
or CPU memory.

if you run

gpuinfo=mcxlab('gpuinfo');

it will return the GPU memory specs.

Generally, even a low-end GPU can run MCX without memory issues
unless you simulate a huge number of time gates (because the global
memory needed by MCX is largely sizeof(float) x size of volume x
number of time gates).

Skimming through your script, I noticed that your # of time gate is just
1. However, your tend/tstep are .5 seconds! Typically, for small domains,
time gates of width on the scale of ns are more than sufficient. There is
no need to use such a long time period. Also after several ns, the photon
weights will be close to numerical zero. So, there is really no contribution
from running it for long time.

Perhaps you can fix this and see if you are getting the same error.

By the way, which mcxlab release are you using? I do not see Line#1090
in the current mcx_core.cu, so I suspect you were using an old release.

Qianqian

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[ALEXANDER P. Dumont]

WHen I run mcxlab('gpuinfo')

I get back:

   name: 'Quadro M5000'

            id: 1

      devcount: 1

         major: 5

         minor: 2

     globalmem: 8.5899e+09

      constmem: 65536

     sharedmem: 49152

      regcount: 65536

         clock: 1038000

            sm: 16

          core: 2048

     autoblock: 64

    autothread: 32768

       maxgate: 0

>> 

This is a state of the art gpu I am working with, I am struggling to see how it would be running out of memory. I have downlaoded the latest to see if that hasa fixed the problem, I will tell you how it goes.

[ALEXANDER P. Dumont]

I downloaded your most recent file for mcxlab. It still returns 

MCXLAB ERROR -2 in unit mcx_core.cu:1090

Error: out of memory

[Cody Swain]

Did you ever figure out what gave you that error? I am running into the same issue

[Qianqian Fang]

hi Cody

your quoted post was from 2016. can you post the full error message?

if it  says out of memory, it probably just means exactly that, the
array you created (cfg.vol) probably has a large size or the time
gates is too fine for the GPU memory to store.

Qianqian