The ABINIT Users Mailing List ( CLOSED )

[Noam Bernstein <bernstei@dave.nrl.navy.mil>]

On Tue, 1 Apr 2003, Paul Tangney wrote:

> 
> By default, my fortran compiler (xlf ) allows a maximum
> datasize of 128 Mb of memory and a maximum stack size of 32Mb.
.
.
.
> 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

Sadly, this particular bizarre requirement of the IBM AIX compilers is
not relevant to any other system I know of (Linux, SGI, DEC/Compaq
Alpha), and is therefore unlikely to be related to the original
poster's question.

> 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 understand it, going to 64 bit mode makes pointers larger, which
can increase the memory use of the program if lots of pointers are
used (irrelevant for most FORTRAN programs, I guess).  This could
conceivably cause increased likelyhood of swapping or cache misses,
but otherwise shouldn't make a difference.

                                                        Noam Bernstein