[Pw_forum] Error encountered while attempting to allocate a data object.

Paolo Giannozzi giannozz at nest.sns.it
Thu Jan 29 10:53:16 CET 2004

On Thursday 29 January 2004 00:01, Konstantin Kudin wrote:

>  It looks like the amount of memory for "diag:" got
> wrapped around the 32-bit limit and became negative.

that's strange: the amount of memory used is stored in real
numbers, to avoid this kind of problem. Maybe your version 
was still using integer numbers.

> Is there a way to reduce the memory required for a
> given PWSCF job? 

from the manual:
      \item increase the amount of memory you are authorized to use,
            if possible (ask your system guru)
      \item reduce {\tt nbnd} to the strict minimum
      \item use conjugate-gradient or DIIS diagonalization
            ({\tt diagonalization='cg'} or {\tt 'diis'}):
            slower but requires less memory.
      \item in parallel execution, use more processors, or use the
            same number of processors with less pools.
            Remember that parallelization with respect to k-points (pools)
            does not distribute memory: parallelization with respect to
            {\bf R}-- and {\bf G}--space does.
      \item IBM only: if you need more than 256 Mb you must specify it
           at link time (option {\tt -bmaxdata}).
The second and third items are relevant to your case

> Or should I just move to a 64-bit machine with enough physical RAM
> such as an SGI?

or to a parallel machine


Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
Piazza dei Cavalieri 7      I-56126 Pisa, Italy

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