[PPL-devel] [Fwd: Re: About PPL]

[Roberto Bagnara]

-------- Original Message --------
Subject: Re: About PPL
Date: Fri, 18 Mar 2005 06:05:50 -0800 (PST)
From: gulsah yilmaz <gulsahyilmaz20 at yahoo.com>
To: Roberto Bagnara <bagnara at cs.unipr.it>

Mr. Bagnara,

First of all, thanks for your attention. Since Polylib
uses this representation I think you will be familiar
with the representation. I will exlplain what I want
to do:

I have inequalities like:

x+M+N+5 >= 0
y+z+1 >= 0
x+y >= 0
x+z+1 >= 0
z+M+2>=0

and an inequality which include unknown coefficients
like:

(a-b)x+cz+(d+e)M+N >= 0

and by combining these inequalities I want to know the
relation between unknowns like:

a+b>1
d-e+c>M ....


Thanks
Gulsah Yilmaz

--- Roberto Bagnara <bagnara at cs.unipr.it> wrote:
> Dear Gulsah,
> 
> if the file `Makefile' is missing, it is quite
> likely
> you did not configure your build directory.  Please
> follow
> the instructions in the files `README.configure' and
> `INSTALL' (they are part of the library's
> documentation).
> 
> > An example to my problem:
> > The numbers are faik.
> > 
> >    x   y   z   M   N   Constant
> > 1  1   0   0   1   1       5   
> > 1  0   1   1   0   0       1
> > 1  1   1   0   0   0       0
> > 1  1   0   1   0   0       1
> > 1  0   0   1   1   0       2
> > 
> > and  
> > 1  a-b 0   c   d+e 1       0
> > 
> > I want to know the relation between the unknown
> > coefficient a,b,c,d,e. I ask you whether this is
> > possible or not by using PPL.
> 
> Sorry, but the table above means nothing to me:
> I can imagine the columns named `x', `y' and so
> forth contain coefficients of the variables
> with the same names;  I can imagine the column
> named `Constant' gives the inhomogeneous term;
> but I cannot make any sense of the first, unnamed
> column; then I don't know if that is meant to
> represent a set of constraints (equalities?
> non-strict inequalities?  <=?  >=? something else?)
> or a set of generators.
> 
> Can you please explain your problem in the language
> of linear algebra?  Chances are that we will be
> able to answer your question then.
> Cheers,
> 


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-- 
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it