Re: dynamic memory allocation

From: Christian Pilger <>
Date: Wed 14 Feb 2001 17:24:47 +0100

Hi all,

thanks to everybody who responded to my request.

Bill Ross wrote:

> When I tried to start the calulation on my PC (sander_classic, Suse 7.0,
> Kernel 2.2.16, 256MB ram), it stopped with the following message in
> the output-file: "Npairs =13253296 Exceeds Max= 9000000".
> However, the same input files do not give any problems on an SGI Octane
> (R12k, 1GB ram).
> Thus I think the failure on my PC is due to some value, that has to be
> modified in the source code. Can somebody help me with that ?
> And, more generally, how much do the version for different architectures
> differ in terms of restrictions to the size of the system to be examined ?
> Parallel versions can't do dynamic memory allocation and thus
> require static, compile-time sizing in sizes.h. It sounds like
> the PC version is compiled for parallel (mpi) whereas the SGI
> version is compiled for single-cpu.

I'm quite confident, that I didn't compile a parallel version on my PC. I
used the Machine.g77-file.
By modifying the entry MAXPR from 4500000 to 7000000 in sizes.h and
re-compiling sander_classic, I could fix it.

I tried the same job on our XP1000 workstation (TrueUnix64) and received
the following error message:

   ** failed to allocate pair array, bytes: 633154916

Is this the same problem ? I can't try directly to fix it, because I don't
have root-previleges on that machine and our admin is on holidays.
Just for couriosity I checked that file on our SGI-Installation - and it
had (as I expected) the same value for MAXPR 4500000). So, does the
difference in the executables that I observed (SGI: sander_classic worked
without problems, LINUX/XP1000: it does not work until the MAXPR entry is
set to a higher value) arise from the different compilers/architectures ?




 Dr. Christian Pilger

    Istituto di Strutturistica Chimica "Giordano Giacomello"
    C.N.R. - Sezione di Trieste
    Area Science Park - Basovizza
    Strada Statale 14 - Km. 163.5
    I-34012 Trieste/Italy

   Tel.: +39+040+226881
   Fax : +39+040+9221126
Received on Wed Feb 14 2001 - 08:24:47 PST
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