Re: [FLASH-USERS] FW: 3D RM Problem

Shuang -

> Thanks much! Before going into further discussion, let
> me put the question this way: this simulation with base
> block 2x1x1, 5 AMR levels (approximating resolution
> 256x128x128), how much RAM will be necessary approximately?
> "size" command doesn't seem to give the exact information.

You can estimate the memory requirements by multiplying

your equivalent uniform grid size (max case) times

the number of variables (this is a sum of all named DBASE_VAR_NAMES
and DBASE_NUMBER_OF_SPECIES from object/dbase_defines.fh) times

3 (approximate number of unk-sized arrays)

times

8 (number of bytes per word).

If you use 15 variables and if there would be no overhead coming from
the ghost zones this gives a size ~1.5Gb. With 4 ghost zones on each
side and blocks 8^3 this number has to be increased by a factor
(16/8)^3 = 8 giving the final size of order of ~12 Gbytes.

It is a very rough estimate and we are working on some tool which will
be given memory usage estimate during setup stage. I might missed
some instances of unk copies and there might be some memory allocated
by some of the modules you use. In either case, you seem to be using
a good fraction of the memory available on your system.

> > Can you try dbx instead of gdb?
>
> You mean running it with 1 processor, and setting
> maxblocks to a very large number, in order to use
> dbx? I don't know how to debug MPI code with dbx. :(

I am not sure that gdb can recognize Solaris core file and I am
unaware of it ability to debug MPI programs. dbx should tell you if
the core file has the right format, or perhaps that the file is
incomplete. You should also check your shell environment for possible
coredumpsize limits. Small size of your core file (< 1 Gb) may point
in that direction.

The standard MPI-capable graphical debugger on Suns is called
Prism. You should check whether it is available on your system. I do
not have any experience with it.

Hope it is of some help to you.

Best wishes -

Tomek

--
Tue, 12:04 CDT (17:04 GMT), Apr-29-2003
_______________________________________________________________________________
   Tomasz Plewa                                      www:   flash.uchicago.edu
   Computational Physics and Validation Group        email: tomek@uchicago.edu
   The ASCI Flash Center, The University of Chicago  phone: 773.834.3227
   5640 South Ellis, RI 475, Chicago, IL 60637       fax:   773.834.3230
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