[Cado-nfs-discuss] Block Wiedemann (Paul Zimmermann)

Emmanuel Thomé Emmanuel.Thome at inria.fr
Mon Dec 3 15:15:11 CET 2018


On Mon, Dec 03, 2018 at 09:06:29AM -0500, Jhon Alejandro M wrote:
> Mr Zimmermann
> 
> Your answer has been great very helpful. I have successfully executed block
> wiedemann algorithm with matrices greater than 100 rows per 100 columns,
> but with smaller matrices, the following error appears

100 by 100 ???

For matrices of this size, you certainly don't want a complicated
algorithm like block Wiedemann.

What the warning says is basically that you're hitting corner cases
caused by your tiny matrix sizes. Those are by definition irrelevant for
larger attempts.

If you insist, you may put "balancing_options=--reorder=columns" to
bwc.pl ; but really, don't experiment with matrices of this size, unless
you're trying the bw implementation itself.

E.

> 
> -The current code expects a column permutation replicated on rows, not the
> converse. There is little adaptation work, but yet to be done. Maybe you
> could pass "--reorder columns" to mf_bal ?
> 
> I don't understand the message error.  ¿How can I solve it?  or ¿Why does
> the error appears?
> 
> by last. I have been trying to understand the output files of bwc but I
> don`t understand the output format. ¿How should I interpret the K.sols file
> <s1> - <s2>. <J> .txt? I am trying to solve matrices GF(2) but in the
> output appears hex numbers
> 
> Thanks and Regard
> Jhon Melo
> 
> El mié., 21 nov. 2018, 3:55 a. m., paul zimmermann <Paul.Zimmermann at inria.fr>
> escribió:
> 
> >        Hi Jhon,
> >
> > > From: Jhon Alejandro M <alejandromelo at unicauca.edu.co>
> > > Date: Tue, 20 Nov 2018 16:31:06 -0500
> > >
> > > Hello, my name is Jhon. I am university student of Universidad del
> > cauca. I
> > > am implementing Quadratic Sieve algorithm. I am trying to implement Block
> > > Wiedemann algorithm. ¿Can I run just the block-wiedemann part of
> > cado-nfs?
> > > and ¿Exist any example?
> > >
> > > Thanks and Regard
> > > Jhon Melo
> > > Universidad del Cauca Colombia
> >
> > the simplest way to get an example is to run the README example:
> >
> > $ export CADO_DEBUG=true
> > $ ./cado-nfs.py
> > 90377629292003121684002147101760858109247336549001090677693 workdir=/tmp/c60
> >
> > Then look at /tmp/c60/c60.bwc.stdout.1: its first line contains an example
> > of
> > command line of bwc.pl, the Perl script that calls Block Wiedemann.
> >
> > Additional documentation can be found in linalg/bwc/README.
> >
> > Best regards,
> > Paul Zimmermann
> >
> 
> -- 
> 
> 
> *Hacia una
> Universidad comprometida con la Paz Territorial*

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