[sage-combinat-devel] Sage(-Combinat) tutorial during EJCIM 2014?
Dear French Sage-combinat devs, (this is about an upcoming Spring school for French PhD students at the frontier of maths and computer science; if you are not based in France, you may safely ignore this thread). Sylvain Peyronnet m'a contacté pour savoir si nous souhaitions intervenir comme les années précédentes lors de l'École Jeunes Chercheurs 2014. Est-ce que certains d'entre vous seraient intéressés pour participer resp. prendre cela en main? Bonne journée! Nicolas - Forwarded message from Sylvain Peyronnet sylvain.peyron...@lri.fr - Date: Tue, 21 Jan 2014 20:56:02 +0100 From: Sylvain Peyronnet sylvain.peyron...@lri.fr To: gdr...@gdr-im.fr Subject: [gdr-im] EJCIM 2014 ! MERCI DE DIFFUSER LARGEMENT Annonce pour l'EJC-IM 2014 : Ecole Jeunes Chercheurs en Informatique Mathématique (EJC-IM) 2014 31 mars au 4 avril 2014 à Caen https://ejcim2014.greyc.fr/ Bonjour à toutes et tous. Le GDR Informatique Mathématique propose chaque année une école pour les jeunes chercheurs. L'édition 2014 de ces EJC-IM est organisée par l'équipe AMACC du GREYC, laboratoire de recherche en informatique de l'Université de Caen Basse-Normandie (UCBN). Elle aura lieu sur le campus 3 de l'UCBN, du lundi 30 mars au vendredi 4 avril 2014. Des pré-inscriptions sont obligatoires et ouvertes à partir 24 janvier et jusqu'au 28 février. Nous invitons les jeunes chercheurs participants potentiels à se pré-inscrire sur le site web dès le 24 janvier. Les grands thèmes du GDR IM sont l'algorithmique, la combinatoire, le calcul formel, l'arithmétique, la protection de l'information, la géométrie, la logique et la complexité. L'une des vocations de ces EJC-IM est de promouvoir l'ouverture des jeunes chercheurs à ces thématiques et de renforcer la cohésion scientifique de la communauté Informatique Mathématique. Le public de ces écoles est prioritairement celui des doctorants et jeunes docteurs du GDR IM, mais aussi des étudiants de Master ou des chercheurs d'autres GDR. Cette année, l'école permettra d'aborder les thèmes suivants. * Automates Cellulaires * Algorithmique du web * Exemples d'analyse d'algorithmes en arithmétique et en théorie de l'Information * Complexité de communication * Cryptographie Les jeunes chercheurs sont aussi invités à exposer leurs travaux, sous la forme de présentations orales ou de posters, et ont ainsi l'occasion d'interagir avec la communauté. Les cours qui représentent 15 à 20h de formation sont validés par la plupart des écoles doctorales (attestation fournie sur demande). Les frais d'hébergement du dimanche soir au vendredi midi et la demi-pension (matin et midi) sont pris en charge par l'organisation. Les frais de transport sont à la charge des participants, ainsi que les frais d'inscription de 75 euros. Les modalités de paiement seront communiquées dans les prochaines semaines. Le comité scientifique est composé de : – Valérie Berthé (LIAFA, Paris) – Philippe Langlois (LIRMM, Perpignan) – Jean-Michel Muller (ENS Lyon) – Sylvain Peyronnet (GREYC, Caen) – Natacha Portier (LIP, ENS Lyon) – Brigitte Vallée (GREYC, Caen) Le comité d'organisation est composé de : – Ali Akhavi (GREYC, Caen) – Nicolas Bacquey (GREYC, Caen) – Thomas Largillier (GREYC, Caen) – Sylvain Peyronnet (GREYC, Caen) – Natacha Portier (LIP, ENS Lyon) – Gaëtan Richard (GREYC, Caen) – Brigitte Vallée (GREYC, Caen) Pour plus de détails, n'hésitez pas à consulter la page web de l'école ou à contacter Sylvain Peyronnet (sylvain.peyron...@unicaen.fr). - End forwarded message - Nicolas -- Nicolas M. Thiéry Isil nthi...@users.sf.net http://Nicolas.Thiery.name/ -- You received this message because you are subscribed to the Google Groups sage-combinat-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-combinat-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-combinat-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-combinat-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-combinat-devel] Sage(-Combinat) tutorial during EJCIM 2014?
Je veux bien donner un coup de main si c'est dans mes cordes. Cordialement, Matthieu Le Mercredi 22 janvier 2014 9h38, Nicolas M. Thiery nicolas.thi...@u-psud.fr a écrit : Dear French Sage-combinat devs, (this is about an upcoming Spring school for French PhD students at the frontier of maths and computer science; if you are not based in France, you may safely ignore this thread). Sylvain Peyronnet m'a contacté pour savoir si nous souhaitions intervenir comme les années précédentes lors de l'École Jeunes Chercheurs 2014. Est-ce que certains d'entre vous seraient intéressés pour participer resp. prendre cela en main? Bonne journée! Nicolas - Forwarded message from Sylvain Peyronnet sylvain.peyron...@lri.fr - Date: Tue, 21 Jan 2014 20:56:02 +0100 From: Sylvain Peyronnet sylvain.peyron...@lri.fr To: gdr...@gdr-im.fr Subject: [gdr-im] EJCIM 2014 ! MERCI DE DIFFUSER LARGEMENT Annonce pour l'EJC-IM 2014 : Ecole Jeunes Chercheurs en Informatique Mathématique (EJC-IM) 2014 31 mars au 4 avril 2014 à Caen https://ejcim2014.greyc.fr/ Bonjour à toutes et tous. Le GDR Informatique Mathématique propose chaque année une école pour les jeunes chercheurs. L'édition 2014 de ces EJC-IM est organisée par l'équipe AMACC du GREYC, laboratoire de recherche en informatique de l'Université de Caen Basse-Normandie (UCBN). Elle aura lieu sur le campus 3 de l'UCBN, du lundi 30 mars au vendredi 4 avril 2014. Des pré-inscriptions sont obligatoires et ouvertes à partir 24 janvier et jusqu'au 28 février. Nous invitons les jeunes chercheurs participants potentiels à se pré-inscrire sur le site web dès le 24 janvier. Les grands thèmes du GDR IM sont l'algorithmique, la combinatoire, le calcul formel, l'arithmétique, la protection de l'information, la géométrie, la logique et la complexité. L'une des vocations de ces EJC-IM est de promouvoir l'ouverture des jeunes chercheurs à ces thématiques et de renforcer la cohésion scientifique de la communauté Informatique Mathématique. Le public de ces écoles est prioritairement celui des doctorants et jeunes docteurs du GDR IM, mais aussi des étudiants de Master ou des chercheurs d'autres GDR. Cette année, l'école permettra d'aborder les thèmes suivants. * Automates Cellulaires * Algorithmique du web * Exemples d'analyse d'algorithmes en arithmétique et en théorie de l'Information * Complexité de communication * Cryptographie Les jeunes chercheurs sont aussi invités à exposer leurs travaux, sous la forme de présentations orales ou de posters, et ont ainsi l'occasion d'interagir avec la communauté. Les cours qui représentent 15 à 20h de formation sont validés par la plupart des écoles doctorales (attestation fournie sur demande). Les frais d'hébergement du dimanche soir au vendredi midi et la demi-pension (matin et midi) sont pris en charge par l'organisation. Les frais de transport sont à la charge des participants, ainsi que les frais d'inscription de 75 euros. Les modalités de paiement seront communiquées dans les prochaines semaines. Le comité scientifique est composé de : – Valérie Berthé (LIAFA, Paris) – Philippe Langlois (LIRMM, Perpignan) – Jean-Michel Muller (ENS Lyon) – Sylvain Peyronnet (GREYC, Caen) – Natacha Portier (LIP, ENS Lyon) – Brigitte Vallée (GREYC, Caen) Le comité d'organisation est composé de : – Ali Akhavi (GREYC, Caen) – Nicolas Bacquey (GREYC, Caen) – Thomas Largillier (GREYC, Caen) – Sylvain Peyronnet (GREYC, Caen) – Natacha Portier (LIP, ENS Lyon) – Gaëtan Richard (GREYC, Caen) – Brigitte Vallée (GREYC, Caen) Pour plus de détails, n'hésitez pas à consulter la page web de l'école ou à contacter Sylvain Peyronnet (sylvain.peyron...@unicaen.fr). - End forwarded message - Nicolas -- Nicolas M. Thiéry Isil nthi...@users.sf.net http://Nicolas.Thiery.name/ -- You received this message because you are subscribed to the Google Groups sage-combinat-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-combinat-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-combinat-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-combinat-devel. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-combinat-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-combinat-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-combinat-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-combinat-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: upcoming Sage Days
I am not sure about my abilities to solve bugs, but i would sure like to try. My problem is that i need a long paperwork to go to USA, so i cannot attend on short notice. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] Please review #15699: Glibc scanf workaround for ATLAS
On Mon, 20 Jan 2014 08:10:03 -0800 (PST)
Volker Braun vbraun.n...@gmail.com wrote:
http://trac.sagemath.org/ticket/15699
Since I'm currently unable to login to trac, I'll respond here:
Since it is unlikely that scanf will succeed after having failed once
(since it is then stuck somewhere in the middle of 0e+00) the
code in the current patch will just fill the rest of the array with the
last number that succeeded, disregarding anything remaining in the
file. I think we can do better than that. Please find attached a patch
on 540db9e211 (u/vbraun/glibc_scanf_workaround_for_atlas) that uses a
different approach, namely replacing scanf by strtod.
The patch is a bit more complicated than necessary, as checking
end ! = buf instead of errno == 0 end ! = buf *end == '\n'
is probably sufficient for this usecase.
Regards,
Erik Massop
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From 3a7a922a8012857628d90c2f2625f08210d0c9dc Mon Sep 17 00:00:00 2001
From: Erik Massop e.mas...@hccnet.nl
Date: Wed, 22 Jan 2014 11:47:06 +0100
Subject: [PATCH] Avoid scanf instead of just ignoring rest of file
---
.../atlas/patches/glibc_scanf_workaround.patch | 25 +++---
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/build/pkgs/atlas/patches/glibc_scanf_workaround.patch b/build/pkgs/atlas/patches/glibc_scanf_workaround.patch
index f52eccd..9118aac 100644
--- a/build/pkgs/atlas/patches/glibc_scanf_workaround.patch
+++ b/build/pkgs/atlas/patches/glibc_scanf_workaround.patch
@@ -1,20 +1,29 @@
Bug in glibc-2.18: https://sourceware.org/bugzilla/show_bug.cgi?id=15917
-Patch taken from openSUSE 13.1
--- a/tune/sysinfo/masrch.c
+++ b/tune/sysinfo/masrch.c
-@@ -113,7 +113,12 @@ double matime
+@@ -1,6 +1,7 @@
+ #include stdio.h
+ #include stdlib.h
+ #include assert.h
++#include errno.h
+
+ #ifndef NTIM
+#define NTIM 3
+@@ -113,7 +114,14 @@
j = 0;
for (i=0; i != NTIM; i++)
{
- assert( fscanf(fp, %lf, mflop[i]) );
-+ if(fscanf(fp, %lf, mflop[i])==0) {
-+ if (i0)
-+mflop[i]=mflop[i-1];
-+ else
-+assert(0);
-+ }
++ /* FIXME: This assumes one float per line immediately followed by \n. */
++ char buf[100]; /* enough to read a double */
++ char *end;
++
++ assert(fgets(buf, sizeof buf, fp));
++ errno = 0;
++ mflop[i] = strtod(buf, end);
++ assert(errno == 0 end != buf *end == '\n');
}
fclose(fp);
/*
--
1.8.5.2
[sage-devel] polynomials are power series?
While the ring type hierarchy does not reflect that polynomials are power series, you can have a power series without bigoh which is pratically a polynomial but, being a power series, has much less member functions available. I think Sage shouldn't allow a zero bigoh term in power series. It should avoid unexpected behaviour, eg. users complaining that a polynomial isn't what it seems. But I'm writing here to ask for your opinion before I think about patching, because I'm only beginning to understand Sage, and I'm not even a mathematician! Regards, Ralf Stephan -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] Re: Precision problems in taking determinant?
Is the default choice of the algorithm the right one? One can see that sage: A.determinant(algorithm=hessenberg) 16801.7979988558 is quite good... On Monday, 20 January 2014 18:10:43 UTC, Peter Bruin wrote: Would it be proper to autoconvert matrices over RR to RDF in case of the default precision, so that the more stable numerical algorithms from RDF can be used? I had proposed one such change in #13660 ( http://trac.sagemath.org/13660 ) in case of eigenvalue/eigenvector computations. Well, it should also be fixed for a RealField of higher precision. An easy solution for that is to use PARI, which uses a numerically more stable algorithm (Gaussian elimination, choosing pivots of maximal absolute value; I don't know about proven error bounds). Example: sage: A._pari_().matdet() 16801.7979988279 # same as when doing the computation over QQ Sage's determinant() already uses PARI over Z/nZ for n less than the machine word size; it would be trivial to adapt it to work also over the reals. Peter -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: polynomials are power series?
Thank you, Ralf, for considering ideas how to improve Sage. I can't, however, agree with this particular idea. Think of coercion. You have a polynomial, coerce it into the power series ring, and then? Choose the precision = degree + 1? How could that be a ring homomorpism. You would sacrifice structure for the idea what looks the same should be the same. I don't think the latter is important enough to justify the former. Martin Am Mittwoch, 22. Januar 2014 12:49:01 UTC+1 schrieb Ralf Stephan: While the ring type hierarchy does not reflect that polynomials are power series, you can have a power series without bigoh which is pratically a polynomial but, being a power series, has much less member functions available. I think Sage shouldn't allow a zero bigoh term in power series. It should avoid unexpected behaviour, eg. users complaining that a polynomial isn't what it seems. But I'm writing here to ask for your opinion before I think about patching, because I'm only beginning to understand Sage, and I'm not even a mathematician! Regards, Ralf Stephan -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: Cannot login to trac webinterface
I'll take care of it On Wednesday, January 22, 2014 10:22:45 AM UTC, Erik Massop wrote: Dear list, Getting a 401 Authorization Required at http://trac.sagemath.org/login I punch in my username (emassop) and password (from the latest password-reset e-mail). This does not let me in. Can someone help me with this? Do other people have the same problem? Maybe only after having reset their password? Regards, Erik Massop -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] polynomials are power series?
Surely all Ralf meant was that R[X] is a subring of R[[X]], i.e. some elements of R[[X]] are exact, just as some decimal numbers like 0.25 are exact (in binary), and just as we might want to define a real number as having *exactly* the value 0.25 and not just 0.25 + O(10^-1000) one might want to consider 1+X as an exact power series and not just 1+X+O(X^1000). Of course I amy have misunderstood Ralf (or you)! John On 22 January 2014 11:49, Ralf Stephan gtrw...@gmail.com wrote: While the ring type hierarchy does not reflect that polynomials are power series, you can have a power series without bigoh which is pratically a polynomial but, being a power series, has much less member functions available. I think Sage shouldn't allow a zero bigoh term in power series. It should avoid unexpected behaviour, eg. users complaining that a polynomial isn't what it seems. But I'm writing here to ask for your opinion before I think about patching, because I'm only beginning to understand Sage, and I'm not even a mathematician! Regards, Ralf Stephan -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] polynomials are power series?
I understand precision as being independent from element properties (as it is in Pari). Note also that R.random_element() always has O(x^20) so a fixed precision is already implemented. John is right that I see polynomials as a subring to power series. I would not be able to give references to that however. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: polynomials are power series?
On Wednesday, January 22, 2014 3:49:01 AM UTC-8, Ralf Stephan wrote: While the ring type hierarchy does not reflect that polynomials are power series, you can have a power series without bigoh which is pratically a polynomial but, being a power series, has much less member functions available. As a power series, it has *different* methods available. For instance, the (formal) power series 1-x has a multiplicative inverse (formal) power series 1+x+x^2+x^3+... but the polynomial 1-x does not have a multiplicative inverse polynomial. The big-Oh term is giving you useful information: it is telling you that 1 - x + O(x^10) is considered a power series. You also see why, even if this is the power series representation of the polynomial 1-x and not of a power series 1-x+x^11+x^13+..., it is still essential to have some precision associated to the object: once you take the inverse of a power series, you need a precision to represent it in a finite way (ignoring lazy approaches for now). -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] Re: polynomials are power series?
If polynomials were a subring of power series then 1-x would have an inverse. Who says it has not? (Do not misunderstand me please, I simply don't know) On Wed, Jan 22, 2014 at 4:57 PM, Nils Bruin nbr...@sfu.ca wrote: On Wednesday, January 22, 2014 3:49:01 AM UTC-8, Ralf Stephan wrote: While the ring type hierarchy does not reflect that polynomials are power series, you can have a power series without bigoh which is pratically a polynomial but, being a power series, has much less member functions available. As a power series, it has *different* methods available. For instance, the (formal) power series 1-x has a multiplicative inverse (formal) power series 1+x+x^2+x^3+... but the polynomial 1-x does not have a multiplicative inverse polynomial. The big-Oh term is giving you useful information: it is telling you that 1 - x + O(x^10) is considered a power series. You also see why, even if this is the power series representation of the polynomial 1-x and not of a power series 1-x+x^11+x^13+..., it is still essential to have some precision associated to the object: once you take the inverse of a power series, you need a precision to represent it in a finite way (ignoring lazy approaches for now). -- You received this message because you are subscribed to a topic in the Google Groups sage-devel group. To unsubscribe from this topic, visit https://groups.google.com/d/topic/sage-devel/APnWIGYcq3M/unsubscribe. To unsubscribe from this group and all its topics, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: polynomials are power series?
I will abstain from the type hierarchy. I need to have a better grip on rings. Sorry for the time you wasted. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] Re: polynomials are power series?
It would not have it's inverse in the subring. You need an infinite number of terms to express (1 - x)^-1 = 1 + x + x^2 + x^3 + ... (by using multiplication as 1/(1 - x) is formally a rational function). Currently we have the following behavior in sage: sage: R.x = QQ[] sage: f = 1 - x; f -x + 1 sage: f.parent() Univariate Polynomial Ring in x over Rational Field sage: FPS.x = QQ[[]] sage: FPS Power Series Ring in x over Rational Field sage: FPS(f) 1 - x sage: _.parent() Power Series Ring in x over Rational Field sage: f + x 1 sage: FPS(f)^-1 1 + x + x^2 + x^3 + x^4 + x^5 + x^6 + x^7 + x^8 + x^9 + x^10 + x^11 + x^12 +x ^13 + x^14 + x^15 + x^16 + x^17 + x^18 + x^19 + O(x^20) sage: f^-1 1/(-x + 1) sage: _.parent() # This is the field of rational functions Fraction Field of Univariate Polynomial Ring in x over Rational Field so it looks like the 0*O(x^20) is just suppressed from the output in the (formal) power series ring. Best, Travis On Wednesday, January 22, 2014 8:01:17 AM UTC-8, Ralf Stephan wrote: If polynomials were a subring of power series then 1-x would have an inverse. Who says it has not? (Do not misunderstand me please, I simply don't know) On Wed, Jan 22, 2014 at 4:57 PM, Nils Bruin nbr...@sfu.ca javascript:wrote: On Wednesday, January 22, 2014 3:49:01 AM UTC-8, Ralf Stephan wrote: While the ring type hierarchy does not reflect that polynomials are power series, you can have a power series without bigoh which is pratically a polynomial but, being a power series, has much less member functions available. As a power series, it has *different* methods available. For instance, the (formal) power series 1-x has a multiplicative inverse (formal) power series 1+x+x^2+x^3+... but the polynomial 1-x does not have a multiplicative inverse polynomial. The big-Oh term is giving you useful information: it is telling you that 1 - x + O(x^10) is considered a power series. You also see why, even if this is the power series representation of the polynomial 1-x and not of a power series 1-x+x^11+x^13+..., it is still essential to have some precision associated to the object: once you take the inverse of a power series, you need a precision to represent it in a finite way (ignoring lazy approaches for now). -- You received this message because you are subscribed to a topic in the Google Groups sage-devel group. To unsubscribe from this topic, visit https://groups.google.com/d/topic/sage-devel/APnWIGYcq3M/unsubscribe. To unsubscribe from this group and all its topics, send an email to sage-devel+...@googlegroups.com javascript:. To post to this group, send email to sage-...@googlegroups.comjavascript: . Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] math software and China
May be software piracy is not the problem (or there are other problems). Consider for example scilab, which is a free replacement for Matlab (at least partially): it has a huge success in China, even if it is very easy to get non official versions of matlab for only some Yuans. But Scilab is quite an official software in China, with software contests for students! Have a look at this: http://www.scilab.org.cn/ Le 21/01/2014 15:06, John Cremona a écrit : I do know someone in Beiljing who does want to run a Sage Days -- there was a posting to this list a few months ago. He is Zhibin Liang and did a number theory PhD in Cambridge (UK) not long ago. If China has such huge resource then surely someone there could run a Sage notebook server. Are they somehow asking for someone outside China to provide one which can be used from China? Surely any open Sage server could be used from there? John On 21 January 2014 13:53, kcrisman kcris...@gmail.com wrote: Strange subject line, right? But read this post from ask.sagemath: +++ thank you very much! better a notebook servers to China,there are at least 600.000.000 people in internet. many kinds of Python books in China bookstore,but no many people deeply study it. in China,many people use mathematica,because mathematica 9.01 and maple 17 is free download every where magma 2.15 free download in China. in China nobody and no college pay magma V2.20,if pay one times,magma V2.20 will be free downloaded all China in China,95/100 windows OS are free downloaded,no pay a cent to Bill_gate +++ Well, I guess the situation with respect to software piracy in China (and presumably elsewhere) is well-known. I especially find the quote about Magma v2.20 interesting. Anyway, what are the implications of this for Sage - even the cloud? I have no prediction, but it seems pretty important. Certainly one issue this same poster has mentioned before is that the Great Firewall causes problems (see William and cjsh's brief conversation at http://ask.sagemath.org/question/3227/ ). So I think that this is worth discussing, especially if an entire huge country is essentially committed to proprietary software because it doesn't function in a proprietary way there; it makes some practical arguments for open source rather less compelling. Are there any researchers thinking of planning a Sage Days in the PRC? That would be really ground-breaking. - kcrisman -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out. attachment: tdumont.vcf
Re: [sage-devel] polynomials are power series?
Hi Ralf, I understand precision as being independent from element properties (as it is in Pari). In Sage, there are two kinds of precision: the precision of an individual element and the default precision of the power series ring. The same power series ring can contain elements that are represented using different precisions; for example, you can have a power series ring R with default precision 20, an element f in R with precision 10, and another element g in R with infinite precision. An operation on power series (addition, inversion etc.) return the result in the highest precision to which it is defined; this depends on the precision of the elements, not on the default precision. The exception is when the input has infinite precision and the output cannot be represented with infinite precision. This is where the default precision comes in. For example, 1 - x has infinite precision, but 1/(1 - x) = 1 + x + x^2 + x^3 + ... cannot be represented exactly as a power series, so it is truncated to the default precision. In PARI the situation is similar, except for two things: (1) there is no distinction between polynomials and power series of infinite precision that happen to be polynomials, and (2) the default precision is a global setting, not tied to any specific ring. Both of these are simply because PARI has no (explicit) concept of polynomial rings and power series rings. Peter -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] Re: polynomials are power series?
Hi Travis, so it looks like the 0*O(x^20) is just suppressed from the output in the (formal) power series ring. If you mean that this is suppressed when printing FPS(f): no, actually FPS(f) has infinite precision, even though its parent FPS has a finite default precision. Only when computing 1/f does the O(x^20) arise; the default precision is used here because the result cannot be expressed as a power series with infinite precision. Peter -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] Re: Precision problems in taking determinant?
Hi Dima, Is the default choice of the algorithm the right one? One can see that sage: A.determinant(algorithm=hessenberg) 16801.7979988558 is quite good... The PARI documentation of the function charpoly() says: If flag=2, uses the Hessenberg form. Assumes that the base ring is a field. Uses $O(n^3)$ scalar operations, but suffers from coefficient explosion unless the base field is finite or $\R$. Since the determinant is just the constant term of the characteristic polynomial, this looks safe for the determinant as well. I guess the question whether we should use Sage's built-in Hessenberg algorithm or PARI's matdet() comes down to which of the two is faster. Peter -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] polynomials are power series?
Thanks Travis, so there is coercion already. Now I think it natural to also have coercion from the polynomial fractions to power series, or at least have an expand() member function with a precision parameter and coercion in case of addition with some bigoh, see http://trac.sagemath.org/ticket/15698 And thanks to Peter for completely clarifying power series precision. On Wed, Jan 22, 2014 at 5:36 PM, Peter Bruin pjbr...@gmail.com wrote: Hi Ralf, I understand precision as being independent from element properties (as it is in Pari). In Sage, there are two kinds of precision: the precision of an individual element and the default precision of the power series ring. The same power series ring can contain elements that are represented using different precisions; for example, you can have a power series ring R with default precision 20, an element f in R with precision 10, and another element g in R with infinite precision. An operation on power series (addition, inversion etc.) return the result in the highest precision to which it is defined; this depends on the precision of the elements, not on the default precision. The exception is when the input has infinite precision and the output cannot be represented with infinite precision. This is where the default precision comes in. For example, 1 - x has infinite precision, but 1/(1 - x) = 1 + x + x^2 + x^3 + ... cannot be represented exactly as a power series, so it is truncated to the default precision. In PARI the situation is similar, except for two things: (1) there is no distinction between polynomials and power series of infinite precision that happen to be polynomials, and (2) the default precision is a global setting, not tied to any specific ring. Both of these are simply because PARI has no (explicit) concept of polynomial rings and power series rings. Peter -- You received this message because you are subscribed to a topic in the Google Groups sage-devel group. To unsubscribe from this topic, visit https://groups.google.com/d/topic/sage-devel/APnWIGYcq3M/unsubscribe. To unsubscribe from this group and all its topics, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] Re: polynomials are power series?
Ah, I see. Thanks for clarifying that for me Peter. On Wednesday, January 22, 2014 8:41:24 AM UTC-8, Peter Bruin wrote: Hi Travis, so it looks like the 0*O(x^20) is just suppressed from the output in the (formal) power series ring. If you mean that this is suppressed when printing FPS(f): no, actually FPS(f) has infinite precision, even though its parent FPS has a finite default precision. Only when computing 1/f does the O(x^20) arise; the default precision is used here because the result cannot be expressed as a power series with infinite precision. Peter -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: Python class inheriting from MPolynomialRing_libsingular?
On Tuesday, January 21, 2014 1:47:47 PM UTC-8, Simon King wrote: I don't understand what is the problem with the Python class. Please enlighten me! I don't either, but I'll share some of my observations from the traceback. The libsingular init calls as a first thing MPolynomialRing_generic.__init__ which ends up triggering: sage/categories/algebras.py:159 154except AssertionError: 155pass 156return 157 158try: 159one = self.one() which looks like trouble to me, since the libsingular code only later sets self._one_element = one, where `one` is an explicitly Is it perhaps some type issue (where it explicitly tests for libsingular rings to avoid doing something) or the existence of a self.__dict__ that makes categories/algebras try to get the one element? In this order, you'll trigger the generic x=self(1) implementation of `one` which will wreak havoc: the underlying libsingular ring isn't even instantiated yet! You might be able to make the code more robust by seeing if you can rearrange MPolynomial_libsingular.__init__ to only call the generic __init__ once the libsingular-specific attributes have been filled in. It may seem weird, but as you can see, apparently a part of the category-based initialization stuff expects to be passed fully functional rings during initialization, so that suggests tail calls in the __init__ hierarchy rather than head calls. It would be good to identify why this isn't giving problems on a cdef class. The code that triggers the problem sits in sage.categories.algebras.Algebras.ParentMethods.__init_extra__ so the ease with which you can track down the problem will be a good test for how viable the category dynamic class stuff is in practice. -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-devel] Re: Precision problems in taking determinant?
Hi Peter, On Wednesday, 22 January 2014 16:53:43 UTC, Peter Bruin wrote: Is the default choice of the algorithm the right one? One can see that sage: A.determinant(algorithm=hessenberg) 16801.7979988558 is quite good... The PARI documentation of the function charpoly() says: If flag=2, uses the Hessenberg form. Assumes that the base ring is a field. Uses $O(n^3)$ scalar operations, but suffers from coefficient explosion unless the base field is finite or $\R$. Since the determinant is just the constant term of the characteristic polynomial, this looks safe for the determinant as well. Sage computes det() by computing charpoly(0), too... The division-free algorithm is obviously meant for more general setting of rings, not fields. I don't know why it was made default here, perhaps just an oversight. I guess the question whether we should use Sage's built-in Hessenberg algorithm or PARI's matdet() comes down to which of the two is faster. for charpoly(), that is. Peter -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: math software and China
On Tuesday, 21 January 2014 13:53:17 UTC, kcrisman wrote: Strange subject line, right? But read this post from ask.sagemath: +++ thank you very much! better a notebook servers to China,there are at least 600.000.000 people in internet. many kinds of Python books in China bookstore,but no many people deeply study it. in China,many people use mathematica,because mathematica 9.01 and maple 17 is free download every where magma 2.15 free download in China. in China nobody and no college pay magma V2.20,if pay one times,magma V2.20 will be free downloaded all China in China,95/100 windows OS are free downloaded,no pay a cent to Bill_gate +++ Well, I guess the situation with respect to software piracy in China (and presumably elsewhere) is well-known. I especially find the quote about Magma v2.20 interesting. Russia used to be quite similar in this respect - largely due to abundance of pirated wares things like Linux etc weren't too popular. Anyway, what are the implications of this for Sage - even the cloud? I have no prediction, but it seems pretty important. Certainly one issue this same poster has mentioned before is that the Great Firewall causes problems (see William and cjsh's brief conversation at http://ask.sagemath.org/question/3227/ ). So I think that this is worth discussing, especially if an entire huge country is essentially committed to proprietary software because it doesn't function in a proprietary way there; it makes some practical arguments for open source rather less compelling. Are there any researchers thinking of planning a Sage Days in the PRC? That would be really ground-breaking. - kcrisman -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: Python class inheriting from MPolynomialRing_libsingular?
On Wednesday, January 22, 2014 12:32:44 PM UTC-8, Nils Bruin wrote: It would be good to identify why this isn't giving problems on a cdef class. The code that triggers the problem sits in sage.categories.algebras.Algebras.ParentMethods.__init_extra__ so the ease with which you can track down the problem will be a good test for how viable the category dynamic class stuff is in practice. Here's some data. I have Algebras.ParentMethods.__init_extra__ equipped with some print commands and I've adapted your example to use MPolynomialRing_generic instead, because that doesn't segfault. I get sage: from sage.rings.polynomial.multi_polynomial_ring_generic import MPolynomialRing_generic sage: R=MPolynomialRing_generic(QQ,3,['a','b','c'],lex) sage: [C for C in type(R).mro() if __init_extra__ in C.__dict__] [] sage: R.__init_extra__ bound method JoinCategory.parent_class.__init_extra__ of Multivariate Polynomial Ring in a, b, c over Rational Field whereas for a python subclass: sage: class M(MPolynomialRing_generic): pass sage: R=M(QQ,3,['a','b','c'],lex) DEBUG: entering! DEBUG: getting to dangerous part DEBUG: exception has happened sage: [C for C in type(R).mro() if __init_extra__ in C.__dict__] [sage.categories.algebras.Algebras.parent_class, sage.categories.magmas.Magmas.parent_class, sage.categories.commutative_additive_semigroups.CommutativeAdditiveSemigroups.parent_class, sage.categories.additive_magmas.AdditiveMagmas.parent_class] sage: R.__init_extra__ bound method M_with_category.__init_extra__ of Multivariate Polynomial Ring in a, b, c over Rational Field We see that for the python subclass the offending __init_extra__ does get executed, but for the original cdef class it doesn't (in fact the output also shows that the actual command try: one=self.one() fails for M as well, it just doesn't cause the segfault that happens for libsingular. The reason for the difference is also clear once you know that the execution of `__init_extra__` is decided by seeing if it sits in some class.__dict__. For the python class, we see that there are several classes in the mro that indeed have that attribute, but for the cdef class there is not: also none of the dynamic classes sit in the cdef mro, whereas there are lots of dynamic classes in the mro of the type of the python subclass instance. It surprises me that the MPolynomialRing_generic instance does have an __init_extra__ attribute. Where does that come from? does it get supplied by some custom get somewhere? Is it some workaround for the apparent fact that the whole dynamic class business doesn't work for cython classes? If so, then it does so in a way that's incompatible with the code that tries to decide to look up whether __init_extra__ needs to be run: Simon has just found a bug that has been lurking for ages, only because another bug prevented it from being triggered. I must say this particular example increases my scepticism about the black magic the category framework tries to play. If even one of its designers gets stumped by it, do we really want to extend it even further? -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: math software and China
Implications? Well, if you want to make Magma V2.20 free, just get a copy from China. Or Mathematica. etc. The people who break the licensing code might also insert malware, so you might not want to run it on an internet-connected computer. And you might want to be secretive about your little criminal activity. Eventually China might start respecting copyrights; after all there is a Microsoft Research presence in Beijing. Someday. RJF -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: Python class inheriting from MPolynomialRing_libsingular?
On Wednesday, January 22, 2014 8:43:36 PM UTC-8, Nils Bruin wrote: It surprises me that the MPolynomialRing_generic instance does have an __init_extra__ attribute. Where does that come from? does it get supplied by some custom get somewhere? Yes, it does: sage.structure.parent.Parent.__getattr__ claims to look on Parent and on self._category.parent_class for attributes. It tries to cache these things, though. Has it been tested that that is actually necessary? python is supposed to have an attribute lookup cache for types (I can't find a PEP but here's a Python Issue related to it http://bugs.python.org/issue1700288). This cache is pretty necessary for decent performance (its absence in cdef classes was for a while responsible for certain method calls being faster than straight attribute access on objects with long mro's, leading to the mistaken belief that cached no-arg methods were faster than straight attributes. Cython has luckily been fixed since) -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
[sage-devel] Re: Python class inheriting from MPolynomialRing_libsingular?
On Wednesday, January 22, 2014 11:10:24 PM UTC-8, Nils Bruin wrote: sage.structure.parent.Parent.__getattr__ claims to look on Parent and on self._category.parent_class for attributes. Moreover, it makes me wonder why we even bother with dynamic classes: sage: [C.__getattribute__ for C in type(R).mro()] [slot wrapper '__getattribute__' of 'sage.structure.parent.Parent' objects, slot wrapper '__getattribute__' of 'sage.structure.parent.Parent' objects, ...another 7 times ... slot wrapper '__getattribute__' of 'object' objects, ...very many times...] If we're implementing inherited attribute lookup ourselves, why are we bothering doing it 9 times? And why are we adding all these parents to the mro that will not be visited any way for a useful reason, because the first `__getattr__` will already have taken care of the lookup? -- You received this message because you are subscribed to the Google Groups sage-devel group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
