Re: [DebianGIS] grass and 64bit

[Markus Neteler <neteler@itc.it>]

On Thu, Mar 16, 2006 at 11:41:34AM +0100, Francesco P. Lovergine wrote:
> Now that amd64 arch just entered the great main world, I wonder if 
> it would be useful/needed(?) in grass enabling the '64bit support'
> whose use is not so clear to me... 
> 
> 
> (C) COMPILATION NOTES for 64bit platforms
> 
> To successfully compile GRASS on 64bit platforms, the required
> FFTW2 library has to be compiled with -fPIC flag:
> 
>     #applies to FFTW2, not GRASS:
>     cd fftw-2.1.5/
>     CFLAGS="-fPIC" ./configure
>     make
>     make install
> 
> To fully enable 64bit library usage for GRASS on 64bit platforms,
> the following additional parameters are recommended/required:
> 
>     ./configure \
>        --enable-64bit \
>        --with-libs=/usr/lib64 \
>        ...
> 

Francesco,

I am using it for some months now (wrote above notes),
but right, I don't know if I gain anything :-)

Maybe it affects the data storage internally. Since
the GRASS 6 data formats are portable across 32bit/64bit,
I don't know any effective difference. but I am no
expert.

Maybe someone could test the performance by creating
fractal DEMs with r.surf.fractal and generate
vector topology of the GSHHS dataset?

Would be interesting to know!

Markus