[Cado-nfs-discuss] Linalg: contexts size

[paul zimmermann]

       Dear Pierpaolo,

> From: Pierpaolo Santucci <spierpa.net at gmail.com>
> Date: Fri, 26 Jun 2015 19:37:03 +0200
> 
> Hello everyone!
> 
> Using Cado-NFS linear algebra, with m=n=192 and prime=2, I get the
> following error:
> 
> Unsupported combination: group size = 192, p = 2
> Unsupported combination: group size = 192, p = , 1 limbs
> 2, 1 limbs
> 
> What are the supported combinations of m and n?
> Can I use different sizes for right and left contexts?
> 
> Thanks a lot!
> 
> Pierpaolo Santucci

looking at the source code (linalg/bwc/mpfq/mpfq_vbase.c) it seems only 64,
128 and 256 are supported. But when trying n=256 it seems to fail with a
different kind of error:

Cannot find the proper rebinder for data backend = u64k4 and matmul backend = bucket

All combinations of m,n in {64,128} seem to work on the c59 in README.
{m,n} = {256,128} seems ok too.

{m,n} = {256,64} seems to loop forever in linalg.


Best regards,
Paul