[sage-devel] Re: upcoming Sage Days

2014-01-22 Thread mmarco
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

[sage-devel] Cannot login to trac webinterface

2014-01-22 Thread Erik Massop
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 the

Re: [sage-devel] Please review #15699: Glibc scanf workaround for ATLAS

2014-01-22 Thread Erik Massop
On Mon, 20 Jan 2014 08:10:03 -0800 (PST) Volker Braun 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) th

[sage-devel] polynomials are power series?

2014-01-22 Thread 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 sh

Re: [sage-devel] Re: Precision problems in taking determinant?

2014-01-22 Thread Dima Pasechnik
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

[sage-devel] Re: polynomials are power series?

2014-01-22 Thread Martin Raum
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 s

[sage-devel] Re: Cannot login to trac webinterface

2014-01-22 Thread Volker Braun
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

Re: [sage-devel] polynomials are power series?

2014-01-22 Thread John Cremona
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 co

Re: [sage-devel] polynomials are power series?

2014-01-22 Thread Ralf Stephan
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 th

[sage-devel] Re: polynomials are power series?

2014-01-22 Thread Nils Bruin
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 > av

Re: [sage-devel] Re: polynomials are power series?

2014-01-22 Thread Ralf Stephan
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 wrote: > On Wednesday, January 22, 2014 3:49:01 AM UTC-8, Ralf Stephan wrote: >> >> While the rin

[sage-devel] Re: polynomials are power series?

2014-01-22 Thread Ralf Stephan
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

Re: [sage-devel] Re: polynomials are power series?

2014-01-22 Thread Travis Scrimshaw
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. = QQ[] sage: f = 1 - x; f -x + 1

Re: [sage-devel] math software and China

2014-01-22 Thread Thierry Dumont
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 qui

Re: [sage-devel] polynomials are power series?

2014-01-22 Thread Peter Bruin
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 r

Re: [sage-devel] Re: polynomials are power series?

2014-01-22 Thread Peter Bruin
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 comput

Re: [sage-devel] Re: Precision problems in taking determinant?

2014-01-22 Thread Peter Bruin
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

Re: [sage-devel] polynomials are power series?

2014-01-22 Thread Ralf Stephan
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/1569

Re: [sage-devel] Re: polynomials are power series?

2014-01-22 Thread Travis Scrimshaw
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 printi

[sage-devel] Re: Python class inheriting from MPolynomialRing_libsingular?

2014-01-22 Thread Nils Bruin
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_gene

Re: [sage-devel] Re: Precision problems in taking determinant?

2014-01-22 Thread Dima Pasechnik
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()

[sage-devel] Re: math software and China

2014-01-22 Thread Dima Pasechnik
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 boo

[sage-devel] Re: Python class inheriting from MPolynomialRing_libsingular?

2014-01-22 Thread Nils Bruin
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 tr

[sage-devel] Re: math software and China

2014-01-22 Thread rjf
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 cr

[sage-devel] Re: Python class inheriting from MPolynomialRing_libsingular?

2014-01-22 Thread Nils Bruin
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.Paren

[sage-devel] Re: Python class inheriting from MPolynomialRing_libsingular?

2014-01-22 Thread Nils Bruin
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