[PPL-devel] Fwd: ppl_pips problems

[Albert Cohen]

By the way, let me encourage you all to participate to the upcoming 
IMPACT and ACCA workshops associated with CGO:
   http://www.cgo.org/cgo2011/
   http://www.cgo.org/cgo2011/workshops.php

These are informal events in a nice environment, a good occasion to meet 
and present work in progress.

Albert

> -------- Original Message --------
> Subject: [PPL-devel] ppl_pips problems
> Date: Mon, 31 Jan 2011 16:58:35 +0100
> From: Sven Verdoolaege <skimo-ppl at kotnet.org>
> Reply-To: Sven Verdoolaege <skimo at kotnet.org>
> To: ppl-devel at cs.unipr.it
> CC: Albert Cohen <Albert.Cohen at inria.fr>
>
> I'm in the process of writing a paper about my improvements
> to pip and I wanted to compare to the PPL implementation too.
> (At least, I'd like to compare the execution times. I probably
> won't be diving into source to find out which optimizations in
> isl have also been implemented in PPL.)
>
> However, ppl_pips seems to produce incorrect results on some
> test cases. I'm using version products_root-2871-gc02e988.
> (The git repo does not appear to have any tags for the releases.)
>
> For bart-big.pip, ppl_pips returns
>
> Parameter N = (3*L + 64) div 256
> if N >= 1 and -3*L + 256*N >= 64 then
> {-K + M ; M - 2 ; M - 2 ; M - 2 ; M - 2 ; M - 2 ; M - 2 ; M - 2 ; M - 2
> ; M - N}
> else
> _|_
>
> Which essentially means that it only found a solutions for
> L = 64, while there should be a solution for every value of L
> in the context.
>
> For bouleti.pip, ppl_pips returns
>
> _|_
>
> That is, it claims that there is no solution, while isl_pip
> and PipLib's exampleMP do find solutions. Here is one of them:
> [p0, p1, p2, p3, p4, p5] -> { [1, 11, 4, 1, 2, 1, 2, 2, 1] : p3 = 1 and
> p4 = 11 and p5 = 2 and p0 = 0 and p1 = 0 and p2 = 2 }
>
> The following iscc session demonstrates that this is indeed
> a solution
>
> Q :=
> 24 17
> 1 0 0 0 -1 0 0 0 0 0 1 -1 1 0 0 0 0
> 1 0 0 0 0 0 0 -1 0 0 1 -1 1 0 0 0 0
> 1 0 0 0 0 -1 0 0 0 0 1 -1 1 0 0 0 0
> 1 0 0 0 0 0 0 0 -1 0 1 -1 1 0 0 0 0
> 1 0 0 0 0 0 1 0 0 0 -1 1 0 -1 0 0 0
> 1 -1 0 0 0 0 0 0 0 0 1 -1 0 1 0 0 0
> 1 0 -1 0 0 0 0 0 0 0 1 -1 0 0 1 0 0
> 1 0 0 1 0 0 0 0 0 0 -1 1 0 0 0 -1 -1
> 1 0 0 0 1 0 0 0 0 0 -1 0 0 0 0 0 -1
> 1 0 0 0 1 1 -1 0 0 0 -1 0 0 0 0 0 0
> 1 0 0 -1 0 0 0 2 0 0 -1 0 0 0 0 0 0
> 1 0 0 0 0 0 0 1 0 0 -1 0 0 0 0 0 -1
> 1 0 0 0 0 0 0 1 1 -1 -1 0 0 0 0 0 0
> 1 0 0 0 0 1 0 0 0 0 -1 0 0 0 0 0 -1
> 1 0 0 0 0 0 0 0 1 0 -1 0 0 0 0 0 -1
> 1 0 0 0 0 0 1 0 0 0 -1 0 0 0 0 0 -1
> 1 0 0 0 0 0 0 0 0 1 -1 0 0 0 0 0 -1
> 1 1 1 0 0 0 0 0 0 0 -2 2 0 -1 -1 0 0
> 1 0 0 0 2 0 0 0 0 0 -2 1 0 0 0 -1 0
> 1 0 -1 0 0 0 0 0 4 3 -6 0 0 0 0 0 0
> 1 0 0 0 0 4 3 0 0 0 -7 1 0 0 -1 0 0
> 1 1 1 1 0 0 0 -2 -4 -4 7 0 0 0 0 0 0
> 1 0 0 0 -2 -4 -4 0 0 0 10 -3 0 1 1 1 0
> 1 -1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0
> ;
> {[1, 11, 4, 1, 2, 1, 2, 2, 1, 0, 0, 2, 1, 11, 2]} <= Q;
> True
> C :=
> 1 8
> 1 0 -1 1 0 0 0 -1
> ;
> {[0, 0, 2, 1, 11, 2]} <= C;
> True
>
> Also, I wonder if you have a parser for the output format of
> ppl_pips so that I could compare the results produced by
> ppl_pips with those produced by isl_pip.
>
> skimo
>