Re: Maximum Variable Size in Octave

[Tal Rusak]

Hi,
     Thank you for your fast responses.

Przemek,
     I am just wondering how you were able to use a 10 GB array if the I/O
components of Octave are only 32-bit systems. Wouldn't that cap the
array size at 2 GB? Did you modify any I/O code?

Thanks,
Tal

> On  4-Sep-2008, Przemek Klosowski wrote:
>
> |     I am planning memory-intensive calculations in Octave and/or Matlab.
> |    The Mathwork has published the following document describing the
> |    maximum variable size in Matlab on various platforms:
> |    http://www.mathworks.com/support/tech-notes/1100/1110.html
> |     Is there an equivalent document for Octave?
> |
> | For what it is worth, I compiled octave on a 64-bit itanium system with
> 32 GB
> | of memory and allocated over 10 GB arrays.
>
> If you use --enable-64 (with care to ensure that the libraries you
> link with are also compiled properly for 64-bit indexing; it's still
> an experimental feature) then you should be able to allocate arrays up
> to roughly 2^63 bytes if your operating system will allow it.  But you
> can't read or write arrays larger than approximately 2^31 bytes since
> no one has yet done the work to fix the I/O parts of Octave to be
> 64-bit aware.
>
> On 32-bit systems, you can allocate arrays up to approximately 2^31
> bytes, so that is 2^23 double precision elements.  If you have enough
> memory, you can allocate many arrays of this size, but any single
> array can't be larger than 2^31 bytes.
>
> jwe
>