64 bit Octave

[Russell Standish]

I know this issue has come up a few times in the past, but there have
been some developments...

1) I have succeeded in getting Octave-2.1.50 to compile with native
SGI compilers (MIPS Pro). I've sent the patches through to John Eaton,
so hopefully these will make it into the official sources.

2) Obviously, I can then compile Octave using the 64 bit
compilers. The main reason for doing this is to handle arrays with
more than 256 million elements. (A key differentiator with Matlab, as
Matlab cannot handle arrays bigger than this either). Unfortunately
Octave uses the int data type internally to store index values for
arrays. Somewhat to my surprise, ints are 32 bits wide on Irix, (and also on
Tru64, the only other big memory box I have available at present), so
I'm foiled. There is no way of changing the interpretation of int to
64 bit (unlike the Fortran compiler's -i8 option).

3) I am proposing to replace the relevant int variables with longs -
longs are 64 bits wide on both these systems, and a long==int on a 32
bit system. So my questions to this community are:

   i) Would such a change make a negative difference with other 64 bit
systems - eg Solaris and IA64? I couldn't find any documentation on
the IA64 compilers about the size of int and long

  ii) Are there any comprehensive test suites that could be used to
exercise such a modified Octave to ensure the no bugs have been
introduced?

                                        Cheers

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A/Prof Russell Standish                  Director
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