The ABINIT Users Mailing List ( CLOSED )

[Paul Tangney <tangney@civet.berkeley.edu>]

Hi Jorge,

I have been having similar problems on an SP3 machine. 
I found out the following, and apologise in advance for mistakes....I'm
trying to repeat the computer jargon that I have learned without actually
understanding any of it.

By default, my fortran compiler (xlf ) allows a maximum
datasize of 128 Mb of memory and a maximum stack size of 32Mb.
I think this means that the maximum amount of memory that I can dynamically
allocate in one go is 128Mb and perhaps that the maximum static allocation
is 32Mb (but I'm really not sure what "stacksize" means).
 My hamiltonian matrix needs 390 Mb and so the
program crashes even though I should have 16Gb of memory at my disposal.

In order to cure this the compiler needs a flag which increases this maximum
data size.
The flags for stacksize and datasize are  "-bmaxstack:A" and
"-bmaxdata:B" where A and B
are numbers in hexadecimal. Rather than worrying about hexadecimal, I think
you can 
use "-bmaxdata:0xn0000000" where  n
is the number of units of 256Mb .
For example : "-bmaxdata:0x70000000"  should allow
me to allocate 1792Mb.  
For parallel programs there are some limits on the values that you can use
which are 
imposed by MPI. 

In 64-bit mode there are much larger data allocations allowed by default
and so,
as Michel Cote suggested, this may solve the problem.....but will the program
slow down ?


As I said, I don't understand any of this....I'm trying to interpret what
I read
here :  http://hpcf.nersc.gov/software/ibm/sp_memory.html
and you'll probably have to adapt it to your hardware and compiler.

Regards,

Paul




Jorge Iniguez wrote:
> Dear abinitioners,
>
> I have a problem when trying to run relatively big jobs. The program fails
> to allocate the required amount of memory even though the system has
> enough memory available.
>
> For intance, in the log file I can get something like:
>
> ``Test failed to allocate 1843.383 Mbytes''
>
> but if I type "limit" the system says:
>
> cputime         unlimited
> filesize        unlimited
> datasize        unlimited
> stacksize       524288 kbytes
> coredumpsize    unlimited
> memoryuse       16625280 kbytes
> vmemoryuse      unlimited
> descriptors     200
> threads         1024
>
> i.e., there should not be any memory problem as far as I can see...
>
> The problem happens for both serial and parallel jobs (the above example
> corresponds to a serial job). The job is nothing fanzy: I want to
> calculate energy, forces and stresses for a 22-atom unit-cell system.
> Other details: I am using SGI 2000 with MIPS R14000 Processor and 16 GB
> memory (IRIX 6.5).
>  
> Any help or suggestions would be greatly appreciated!
>  
> Thanks,
>
> Jorge Iniguez
>
>
> ------------------------------------------------------------------------------
>    Jorge Iniguez             Bldg 235, Room E19
>                              NIST Center for Neutron Research
>                              100 Bureau Drive, Mail Stop 8562
>                              Gaithersburg, MD 20899-8562
>                              Phone: 1-301-975-8367 Fax: 1-301-921-9847
>                              E-mail address: jiniguez@nist.gov
> ------------------------------------------------------------------------------