Re: [ESPResSo-users] CUDA error: out of memory

[Stefan Kesselheim]

Hi Markus,
yes, that is quite right. We need 19xN single precision float numbers per LB 
cell, times two, because we stream from one lattice to a second lattice to 
avoid race conditions.
200**3 cells *19 populations * 4 byte * 2 buffers=1216MB,
We need a bit more to save forces and so I'd conclude you have a 2GB GPU.
Cheers
Stefan

On Aug 2, 2013, at 11:01 AM, Markus Gusenbauer <address@hidden> wrote:

> Hi all,
> 
> is the number of nodes with the LBM on GPU limited by hardware? When I choose 
> too large simulation size, I get a CUDA out of memory error.
> Right now I am limited to around 8,320,000 nodes (200x200x208), after that it 
> crashes.
> 
> Example:
> 
> setmd time_step 0.1
> setmd skin 0.2
> thermostat off
> 
> set boxX 200
> set boxY 200
> set boxZ 208
> 
> setmd box_l $boxX $boxY $boxZ
> 
> lbfluid gpu grid 1 dens 1.0 visc 1.5 tau 0.1 friction 0.5
> 
> set cycle 0
> while { $cycle<100 } {
>    puts "$cycle / 100 \r";
> 
>    for { set i 1 } { $i < [expr $boxX-1]} { incr i } {
>        for { set j 1 } { $j < [expr $boxY-1] } { incr j } {
>            for { set k 0 } { $k < 1 } { incr k } {
>                lbnode $i $j $k set u 0.0 0.0 0.001
>            }
>        }
>    }
> 
>    integrate 1
>    incr cycle
> }
> 
> 
> Thanks!
> 
> Markus
>