[Numpy-discussion] Numerical Python and LAPACK on 64-bit machines

Roman Geus geus at inf.ethz.ch
Wed Mar 6 01:27:03 CST 2002


Roy Dragseth wrote:
> 
> On Wednesday 06 March 2002 09:50 am, Roman Geus wrote:
> > Dear Numerical Python user and developers
> >
> > I ran into the following problem:
> >
> > The python application I'm developing uses Numerical Python and other
> > C modules that call LAPACK. My application runs well on 32bit
> > architectures:
> >
> > When I tried to run the application on a HP-UX 64bit machine the
> > application produced bus errors. After a long debugging session I
> > found out that Fortran integers are still 32bit wide on this
> > machine. Therefore also the HP LAPACK library has to called using
> > 32bit integers. Numerical Python however codes Fortran integers as C
> > 'long int' variables, which are 64bit wide on this machine.
> 
> Have you tried the +i8 flag for the HP fortran compiler?  It converts all
> fortran integers to 8bytes entities.
> 
> Regards,
> Roy.

I think this wouldn't help. The optimized BLAS/LAPACK library supplied
by HP expects 32bit integers and other software incorporated into my
python application (e.g. SuperLU) calls BLAS/LAPACK library using 32bit
integers (C 'int' type).

So, what really needs to be changed (at least for this machine) is how
Numerical Python calls BLAS/LAPACK. It also needs to use 32bit integers.
So this means using 'int' instead of 'long int'. 

Regards,
Roman




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