October 2004 - PPL-devel - BUGSENG Mailman

ppl TODO
by Enea Zaffanella 13 Oct '04

13 Oct '04

CVSROOT: /cvs/ppl Module name: ppl Changes by: zaffanella(a)cs.unipr.it 2004-10-13 09:39:04 Modified files: . : TODO Log message: Documentation of affine dimension is now in the user manual. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/TODO.diff?cvsroot=ppl&r1=1.10…

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Re: StInG 1.2
by Roberto Bagnara 12 Oct '04

12 Oct '04

Sriram Sankaranarayanan wrote: > There is this wierd thing I noticed last night, maybe it could be > a minor misunderstanding on my part: > > I was playing around with a prototype for a paper that I am writing, > and this time I am doing memory measurements. > > Since I have pretty printing routines already written up for > C_Polyhedra, I usually put my constraints into a C_Polyhedron p > and then pass it around. This way I do not have to write pretty > printers everytime. > > But then inside a pretty print routine, when I call > > ConSys cs = p.constraints() > > it should just give me the constraints *without* minimizing it.. right? > > But sometimes (for large dimensions), the call actually starts using up > a lot of memory and time. The result is actually a minimized version of > what I passed. This is not bad for my method, but I am wondering > why it does this. In one case, it takes more time for me to print > my invariants than to compute them. Of course, when the printing happens, > I get a minimized set of invariants, but I did not specifically > ask for them. The manual as far as I can see does not say anything > about minimization. Dear Sriram, when the constraints are up-to-date (which is the case after, e.g., computing intersections), Polyhedron::constraints() will simply return them. When they are _not_ up-to-date (which may be the case after, e.g., computing poly-hulls) the constraints must be regenerated from scratch. When this happens, Polyhedron::constraints() may be expensive, and will give you _minimized_ constraints. The library is lazy: if you do not specify that you want minimized constraints you may get them not minimized or minimized; which is the case is an implementation detail (i.e., the behavior in this respect may even change from a PPL release to another). This is not to say that you have not identified a problem in the PPL. If you can provide us with code that we can run to reproduce the behavior you are observing we may be able to say more. It is thanks to one application that we have identified and fixed several avoidable inefficiencies in what will become PPL 0.7. Give us the code and we will make your application (and others) go faster. Cheers, Roberto -- Prof. Roberto Bagnara Computer Science Group Department of Mathematics, University of Parma, Italy http://www.cs.unipr.it/~bagnara/ mailto:bagnara@cs.unipr.it

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ppl/tests Makefile.am generators2.cc addgenera ...
by Enea Zaffanella 11 Oct '04

11 Oct '04

CVSROOT: /cvs/ppl Module name: ppl Changes by: zaffanella(a)cs.unipr.it 2004-10-11 11:58:52 Modified files: tests : Makefile.am generators2.cc Added files: tests : addgenerator5.cc Log message: Tests generators2 and addgenerator5 show a bug in the handling of space dimensions for a generator system corresponding to an empty polyhedron. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/addgenerator5.cc?cvsroo… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/Makefile.am.diff?cvsroo… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/generators2.cc.diff?cvs…

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Multi-dimensional affine transformation?
by Hosung Song 10 Oct '04

10 Oct '04

Dear PPL Developers, Greetings. I have a few questions about affine image operations and some thing else. My understanding about affine transformation impelmentation in PPL is that we have only one-dimensional transformation operations. That is, any transformation is applied only to the specific variable x_k. I'm wondering how I can do affine transformations for all variables x_0,...,x_{n-1} at once. For example, let's think about the 2D transformation as follows. x'' = a*x + b*y + c (1) y'' = d*x + e*y + f (2) Please correct me if my understanding is ever wrong. I would think about doing this 2D transformation by applying 2 1D transformations (which are available in PPL) as: x' = a*x + b*y + c y' = y then x'' = x' y'' = d*x' + e*y' + f . Surely, the results are, in general, not the same as I intended. Am I missing some basic concepts about affine transformations? Or is this just the limitation of PPL? What I'm now thinking to work around this, is, to first add 2 dimensions (x'' & y'') to the original 2D polyhedron (x & y), then add constraints for (1) and (2), then swap x''/y'' with x/y by a mapping function, then remove the higher 2 dimensions (now x & y). Is this a right and necessary approach? Your experienced comments would be greatly appreciated. One more question is, I just skimmed through the new version, but I'm wondering if the C interface of the new version supports the powerset construction. If not, do you think it's quite difficult to add the support? Thanks in advance. Best, Hosung

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Re: Convex hull
by Roberto Bagnara 07 Oct '04

07 Oct '04

Enrico Oliosi wrote: > Ho fatto l'analisi del seguente programma > BEGINPRG > Read(i); > j:=0; > IF (i >= 0) THEN { > j:= i+2; > [p1]={j=0; i>=0; j-i=2} > } ELSE { > j:= i; > [p2]={j=0; -i>0; j-i=0} > } > FI; > [1=0] > ENDPRG > > e quando ho fatto la chiusura convessa utilizzando la chiamata > > [p1].poly_hull_assign_and_minimize([p2]); > > Il risultato e' stato: 1=0. Il poliedro vuoto. Dear Enrico, what you obtain is not surprising at all: since both p1 and p2 are empty polyhedra, their poly-hull is the empty polyhedron. > (se utilizzo la chiamata [p1].poly_hull_assign([p2]) la poly_hull torna > [p2]); This is still OK: the method poly_hull_assign() does not minimize the result and, since p1 is empty it simply gives you back p2. I think that the problem is elsewhere: the constraint `j=0' should not, I believe, be in p1 nor in p2. Please do not hesitate to come back to us if I have not addressed your questions properly. Cheers, Roberto -- Prof. Roberto Bagnara Computer Science Group Department of Mathematics, University of Parma, Italy http://www.cs.unipr.it/~bagnara/ mailto:bagnara@cs.unipr.it

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ppl/tests Makefile.am affineimage9.cc
by Roberto Bagnara 07 Oct '04

07 Oct '04

CVSROOT: /cvs/ppl Module name: ppl Changes by: roberto(a)cs.unipr.it 2004-10-07 15:23:11 Modified files: tests : Makefile.am Added files: tests : affineimage9.cc Log message: New test for Polyhedron::affine_image(). Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/affineimage9.cc?cvsroot… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/Makefile.am.diff?cvsroo…

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ppl/tests polyhull11.cc
by Roberto Bagnara 07 Oct '04

07 Oct '04

CVSROOT: /cvs/ppl Module name: ppl Changes by: roberto(a)cs.unipr.it 2004-10-07 14:59:05 Modified files: tests : polyhull11.cc Log message: Small correction. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/polyhull11.cc.diff?cvsr…

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ppl/tests Makefile.am polyhull11.cc
by Roberto Bagnara 07 Oct '04

07 Oct '04

CVSROOT: /cvs/ppl Module name: ppl Changes by: roberto(a)cs.unipr.it 2004-10-07 12:57:03 Modified files: tests : Makefile.am Added files: tests : polyhull11.cc Log message: New test for Polyhedron::poly_hull_assign_and_minimize(). Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/polyhull11.cc?cvsroot=p… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/Makefile.am.diff?cvsroo…

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ppl/tests polyhull10.cc
by Roberto Bagnara 07 Oct '04

07 Oct '04

CVSROOT: /cvs/ppl Module name: ppl Changes by: roberto(a)cs.unipr.it 2004-10-07 12:22:26 Modified files: tests : polyhull10.cc Log message: Completed. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/tests/polyhull10.cc.diff?cvsr…

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ppl/src Makefile.am checked.defs.hh checked.in ...
by Abramo Bagnara 03 Oct '04

03 Oct '04

CVSROOT: /cvs/ppl Module name: ppl Branch: altnum Changes by: abramo(a)cs.unipr.it 2004-10-03 15:33:51 Modified files: src : Makefile.am checked.defs.hh checked.inlines.hh checked_float.inlines.hh checked_int.inlines.hh checked_mpz.inlines.hh Log message: Transformed implicit default implementation in esplicit specializations using generic implementation. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/src/Makefile.am.diff?cvsroot=… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/src/checked.defs.hh.diff?cvsr… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/src/checked.inlines.hh.diff?c… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/src/checked_float.inlines.hh.… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/src/checked_int.inlines.hh.di… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/ppl/src/checked_mpz.inlines.hh.di…

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