[PPL-devel] integer versus rational solutions (fwd)

[P M Hill]

I also have the same problem. We'll fix the problem asap but, in the 
meantime, the git anonymous access should let you grab a copy.

Pat

On Thu, 9 Jul 2009, Michael Classen wrote:

> Hello Patricia,
>
> thanks for the effort! I just have a simple technical question: I just
> tried to check out the latest snapshot of the "products" branch from
> the GIT web access:
> http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=shortlog;h=refs/heads/products
>
> But it seems that the resulting .tar.gz file is somehow not in any
> format that gzip can handle:
>
> 2677> tar xvzf ppl-a648638a1c5f2b288e03625b5dc07a2bc69d9bd8.tar.gz
> gzip: stdin: not in gzip format
> tar: Child returned status 1
> tar: Error exit delayed from previous errors
>
> Is there anything obvious wrong with what I'm doing here? I also tried
> a few other snapshots and also some graphical archive program, but to
> the same result...
>
> greetings,
> Michael
>
> On Thu, Jul 9, 2009 at 10:09 AM, P M Hill<hill at comp.leeds.ac.uk> wrote:
>> Resending to ppl-devel.
>>
>> ---------- Forwarded message ----------
>> Date: Wed, 8 Jul 2009 14:24:15 +0100 (BST)
>> From: P M Hill <hill at comp.leeds.ac.uk>
>> To: Tobias Grosser <grosser at fim.uni-passau.de>
>> Cc: "gcc-graphite at googlegroups.com" <gcc-graphite at googlegroups.com>,
>>    ppl-devel <ppl-devel at cs.unipr.it>
>> Subject: Re: [PPL-devel] integer versus rational solutions
>>
>> On Wed, 8 Jul 2009, Tobias Grosser wrote:
>>
>>> Hi,
>>>
>>> I just tried to use the ppl to work with integer polyhedron, however I
>>> am stuck with the examples in the documentation for the
>>> Partial_Reduced_Product:
>>>
>>>
>>> http://www.cs.unipr.it/ppl/Documentation/user/ppl-user-0.10.2-html/classParma__Polyhedra__Library_1_1Partially__Reduced__Product.html#_details
>>>
>>> ---------------------------------------------------------------------
>>> In all the examples it is assumed that the template R is the
>>> No_Reduction<D1, D2> class and that variables x and y are defined (where
>>> they are used) as follows:
>>>         Variable x(0);
>>>         Variable y(1);
>>>
>>> Example 1
>>>       The following code builds a direct product of a Grid and NNC
>>>       Polyhedron, corresponding to the positive even integer pairs in
>>>       R^2, given as a system of congruences:
>>>
>>>         Congruence_System cgs;
>>>         cgs.insert((x %= 0) / 2);
>>>         cgs.insert((y %= 0) / 2);
>>>         Partially_Reduced_Product<Grid, NNC_Polyhedron, No_Reduction<D1,
>>> D2> >
>>>           dp(cgs);
>>>         dp.add_constraint(x >= 0);
>>>         dp.add_constraint(y >= 0);
>>>
>>> Example 2
>>>       The following code builds the same product in R^2:
>>>       Partially_Reduced_Product<Grid, NNC_Polyhedron, No_Reduction<D1, D2>
>>>> dp(2);
>>>         dp.add_constraint(x >= 0);
>>>         dp.add_constraint(y >= 0);
>>>         dp.add_congruence((x %= 0) / 2);
>>>         dp.add_congruence((y %= 0) / 2);
>>> ---------------------------------------------------------------------
>>
>> Hi Tobias,
>>
>>>
>>> I would like to create the set of even positive integer pairs, so I
>>> tried Example 1 and 2. With both I have the same problems.
>>>
>>> 1. D1 and D2 are not defined:
>>>
>>> test.cpp:9: error: 'D1' was not declared in this scope
>>> test.cpp:9: error: 'D2' was not declared in this scope
>>>
>>> So I replace D1 with "Grid" and D2 with "NNC_Polyhedron"
>>
>> That is correct. They have to be specified.
>>
>>>
>>> 2. An exception when adding constrains:
>>
>> Only equalities can be added to a product of a grid and polyhedron,
>> best to use refine_with-...() methods here.
>>
>>>
>>> terminate called after throwing an instance of 'std::invalid_argument'
>>>  what():  PPL::Grid::add_constraint(c):
>>> c is not an equality constraint.
>>>
>>> So I removed the positive constraints.
>>>
>>> 3. An exception when adding congruences:
>>>
>>> terminate called after throwing an instance of 'std::invalid_argument'
>>>  what():  PPL::NNC_Polyhedron::add_congruence(cg):
>>> cg is a non-trivial, proper congruence.
>>>
>>> Do you have any idea what I did wrong?
>>
>> Yes, you have to use refiine_with_constraint()
>> and refine_with_congruence();
>>
>> The add methods cannot be used here unless the constraint/congruence is an
>> equality.
>>
>> There is also another problem in your code in that you cannot build the
>> product directly from the congruences as they cannot be add'ed to the
>> NNC_Polyhedron component. Instead, first build a grid from the congruences
>> and then build the product using the grid.
>>
>> Here is my code, based on your examples, that works here:
>>
>> -------------------------------------------------
>>
>>  /*
>>   Example 1
>>  */
>>
>>          Congruence_System cgs;
>>          cgs.insert((x %= 0) / 2);
>>          cgs.insert((y %= 0) / 2);
>>          Grid gr(cgs);
>>          Partially_Reduced_Product<Grid, NNC_Polyhedron,
>>                                    No_Reduction<Grid, NNC_Polyhedron> >
>>            dp(gr);
>>          dp.refine_with_constraint(x >= 0);
>>          dp.refine_with_constraint(y >= 0);
>>
>> --------------------------------------------------
>>
>>  /*
>> Example 2
>>  */
>>
>>       Partially_Reduced_Product<Grid, NNC_Polyhedron,
>>                                 No_Reduction<Grid, NNC_Polyhedron> >
>>         dp(2);
>>
>>       dp.refine_with_constraint(x >= 0);
>>       dp.refine_with_constraint(y >= 0);
>>       dp.refine_with_congruence((x %= 0) / 2);
>>       dp.refine_with_congruence((y %= 0) / 2);
>>
>> --------------------------------------------------
>>
>> I used here the master branch of the git repository head version. The latest
>> developments for the PPL domain for partially reduced products are in the
>> products branch.
>>
>> HTH. Let me know if you have further queries wrt this domain, we will glad
>> to help.
>>
>> Pat
>> _______________________________________________
>> PPL-devel mailing list
>> PPL-devel at cs.unipr.it
>> http://www.cs.unipr.it/mailman/listinfo/ppl-devel
>>
>