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

Konstantin Kudin konstantin_kudin at yahoo.com
Sat Jan 31 20:28:13 CET 2004


--- Paolo Giannozzi <giannozz at nest.sns.it> wrote:
> 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.

 Actually, the problem with the wrapped around
integers persists even in a recent CVS build. I've
taken a look at memory.f90 and noticed that even
though some of the expressions are assigned to a
floating point number, they contain all integer
arguments and thus are probably evaluated as integers
until the very last assignment.

 A fix that requires not too much typing is to replace
in memory.f90:

>  integer, parameter :: real_size = 8, int_size = 4
>  integer, parameter :: comp_size = 2*real_size

 By the following:
  integer, parameter :: real_size_i = 8, int_size_i =
4
  integer, parameter :: comp_size_i = 2*real_size_i
  real(kind=DP) :: real_size,int_size,comp_size
  ... (and then a bit later) ...
  real_size = float(real_size_i)
  int_size = float(int_size_i)
  comp_size = float(comp_size_i)

 This forces floating point numbers for intermediate
values, and the estimates come out correctly.

 Kostya


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