Re: [sage-devel] How much do we support the casual user

On Tuesday, 27 March 2018 18:03:48 UTC-6, saad khalid wrote: > > Why not assume by default that when someone enters a floating point > number, they intend it as a member of QQ, at least in this case. > It may be an interesting option to have similar to "automatic_names". It may also be nice to

Re: [sage-devel] How much do we support the casual user

On Tuesday, 27 March 2018 13:57:12 UTC-6, Michael Orlitzky wrote: > > But will MATLAB tell you that two equal matrices have different ranks? I > know sage will do it. > A few years back it could give you completely different eigenvalues for a matrix and its transposition. There are presumably

[sage-devel] Re: "not a valid Python identifier" error in desolve_system

The issue boils down to this: sage: var('t');function('u'); sage: laplace(u(t),t,t) laplace(u(t), t, t) sage: laplace(u(t),t,t+3) ValueError: The name "+" is not a valid Python identifier. The error is raised in dummy_laplace called with arguments (u(t),t,t+3), when executing

Re: [sage-devel] How much do we support the casual user

On Tuesday, March 27, 2018 at 2:57:12 PM UTC-5, Michael Orlitzky wrote:The thread was about casual users, who shouldn't have to care about the implementation details behind what "0.5" means. To a casual user, 0.5 is one-half. I didn't bring this up to fight about by pet bug again, but because

[sage-devel] "not a valid Python identifier" error in desolve_system

Running the following code: var('t') function('u')(t) function('v')(t) desolve_system([2*u(t)*sin(t) + diff(u(t),t) == 0, -cos(t)*u(t) + v(t)*sin(t) + diff(v(t),t) == 0], [u(t), v(t)], [0,1,0], t) results in an error message: ValueError: The name "+" is not a valid Python identifier. I have

Re: [sage-devel] How much do we support the casual user

On 03/27/2018 03:11 PM, William Stein wrote: > > Sorry -- I'm not trying to flamebait you, but in order to have any > further discussion, what exactly do you think a floating point number > in a computer is? > What is the mathematical meaning of > float(1) > The thread was about casual

[sage-devel] Re: How much do we support the casual user

Hi Simon, hi Erik, Le mardi 27 mars 2018 21:09:08 UTC+2, Simon King a écrit : > > Hi Erik, > > On 2018-03-27, Erik Bray wrote: > > What about adding an optional argument to the is_prime() > > method--something like a.is_prime(as_element_of=ZZ). It's kind of a > > wordy

Re: [sage-devel] How much do we support the casual user

On Tue, Mar 27, 2018 at 11:54 AM, Michael Orlitzky wrote: > On 03/27/2018 12:22 PM, William Stein wrote: >> >> There are similar examples in MATLAB, involving rational numbers, >> implicit floating point, etc. >> > > Does multiplication by a positive scalar change the rank

[sage-devel] Re: How much do we support the casual user

Hi Erik, On 2018-03-27, Erik Bray wrote: > What about adding an optional argument to the is_prime() > method--something like a.is_prime(as_element_of=ZZ). It's kind of a > wordy (though I'm sure there's a more succinct spelling) way to write > ZZ(a).is_prime() but at

Re: [sage-devel] How much do we support the casual user

On 03/27/2018 12:22 PM, William Stein wrote: > > There are similar examples in MATLAB, involving rational numbers, > implicit floating point, etc. > Does multiplication by a positive scalar change the rank of a matrix? Can two equal matrices have different ranks? (I'm willing to entertain the

Re: [sage-devel] Re: How much do we support the casual user

I've made https://trac.sagemath.org/ticket/25046. David On Tue, Mar 27, 2018 at 2:12 PM, William Stein wrote: > On Tue, Mar 27, 2018 at 11:06 AM, Nils Bruin wrote: > > On Tuesday, March 27, 2018 at 10:48:34 AM UTC-7, Ralf Stephan wrote: > >> > >> Nils, > >> >

Re: [sage-devel] Re: How much do we support the casual user

On Tue, Mar 27, 2018 at 11:06 AM, Nils Bruin wrote: > On Tuesday, March 27, 2018 at 10:48:34 AM UTC-7, Ralf Stephan wrote: >> >> Nils, >> >> See https://trac.sagemath.org/ticket/21067 >> >> for a rational factor_list(). > > > I don't think that helps casual user's API at all. If I

[sage-devel] Re: How much do we support the casual user

On Tuesday, March 27, 2018 at 10:48:34 AM UTC-7, Ralf Stephan wrote: > > Nils, > > See https://trac.sagemath.org/ticket/21067 > > for a rational factor_list(). > I don't think that helps casual user's API at all. If I have to write SR(12/4).factor_list(), I'd rather write ZZ(12/4).factor(). In

[sage-devel] Re: How much do we support the casual user

Nils, See https://trac.sagemath.org/ticket/21067 for a rational factor_list(). -- 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

Re: [sage-devel] Re: How much do we support the casual user

On Tue, Mar 27, 2018 at 9:59 AM, John Cremona wrote: > > > On 27 March 2018 at 17:43, Nils Bruin wrote: >> >> On Tuesday, March 27, 2018 at 9:35:34 AM UTC-7, William wrote: >>> >>> Just curious -- does that have the *potential* to break Magma library >>>

Re: [sage-devel] Re: How much do we support the casual user

On 27 March 2018 at 17:43, Nils Bruin wrote: > On Tuesday, March 27, 2018 at 9:35:34 AM UTC-7, William wrote: >> >> Just curious -- does that have the *potential* to break Magma library >> code? E.g., maybe deep in some package code I wrote 20 years ago >> for Magma, I use

Re: [sage-devel] Re: How much do we support the casual user

On Tuesday, March 27, 2018 at 9:35:34 AM UTC-7, William wrote: > > Just curious -- does that have the *potential* to break Magma library > code? E.g., maybe deep in some package code I wrote 20 years ago > for Magma, I use Factorization on a reational, and assume that the > output is

Re: [sage-devel] Re: How much do we support the casual user

On Tue, Mar 27, 2018 at 9:23 AM, Nils Bruin wrote: > On Tuesday, March 27, 2018 at 12:07:41 AM UTC-7, Ralf Stephan wrote: >> >> Hello, >> I thought I'd try Sage for a casual computation. I was interested in which >> numbers of the form (2^n - (-1)^n)/3 are prime. I first tried out

Re: [sage-devel] How much do we support the casual user

On Tue, Mar 27, 2018 at 9:21 AM Michael Orlitzky wrote: > On 03/27/2018 12:18 PM, William Stein wrote: > > > > I don’t consider that a bug. > > > > I know, but ask anyone without a PhD in math. > There are similar examples in MATLAB, involving rational numbers, implicit

[sage-devel] Re: How much do we support the casual user

On Tuesday, March 27, 2018 at 12:07:41 AM UTC-7, Ralf Stephan wrote: > > Hello, > I thought I'd try Sage for a casual computation. I was interested in which > numbers of the form (2^n - (-1)^n)/3 are prime. I first tried out n=23: > > sage: (2^23+1)/3 > 2796203 > sage: _.is_prime() > False >

Re: [sage-devel] How much do we support the casual user

On 03/27/2018 12:18 PM, William Stein wrote: > > I don’t consider that a bug.  > I know, but ask anyone without a PhD in math. -- 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,

Re: [sage-devel] How much do we support the casual user

On Tue, Mar 27, 2018 at 8:40 AM Michael Orlitzky wrote: > On 03/27/2018 03:07 AM, Ralf Stephan wrote: > > Hello, > > I thought I'd try Sage for a casual computation. > > My favorite bug from when I was an undergrad... > > sage: B = matrix([[ -3, 2, 1 ], > :

Re: [sage-devel] How much do we support the casual user

On 03/27/2018 03:07 AM, Ralf Stephan wrote: > Hello, > I thought I'd try Sage for a casual computation. My favorite bug from when I was an undergrad... sage: B = matrix([[ -3, 2, 1 ], : [ 2,-4, 4 ], : [ 1, 2,-5 ]]) sage: B.rank() 2 sage:

[sage-devel] Re: Possible bug in gen_legendre_P (associated Legendre polynomials)

On Tuesday, March 27, 2018 at 11:20:02 AM UTC+2, James Womack wrote: > > I have created a ticket on Sage trac for this issue: > https://trac.sagemath.org/ticket/25034 > Thanks. > As I mention in the ticket, I think that this issue raises a question as > to whether the Func_assoc_legendre_P

Re: [sage-devel] Re: How much do we support optional packages.

On Sun, Mar 25, 2018 at 4:49 PM, Simon King wrote: > Hi! > > On 2018-03-25, Volker Braun wrote: >> On Sunday, March 25, 2018 at 2:51:46 PM UTC+2, Dima Pasechnik wrote: >>> >>> one can install autotools on archlinux systemwide >>> >> >> Also,

Re: [sage-devel] Re: Re: How much do we support the casual user

On Tue, Mar 27, 2018 at 11:21 AM, Marc Mezzarobba wrote: > John Cremona wrote: >> However pedantic you are it is very hard indeed to justify this for a >> package which is intended for a wide class of users: >> >> sage: a = 300/100 >> sage: a >> 3 >> sage: a in ZZ >> True >>

[sage-devel] Re: Re: How much do we support the casual user

John Cremona wrote: > However pedantic you are it is very hard indeed to justify this for a > package which is intended for a wide class of users: > > sage: a = 300/100 > sage: a > 3 > sage: a in ZZ > True > sage: a.is_prime() > False Yes, but having a.is_prime() return True may break generic

[sage-devel] Re: Possible bug in gen_legendre_P (associated Legendre polynomials)

I have created a ticket on Sage trac for this issue: https://trac.sagemath.org/ticket/25034 As I mention in the ticket, I think that this issue raises a question as to whether the Func_assoc_legendre_P class is correctly defined, given that it now seems to cover both the Ferrers and associated

Re: [sage-devel] Re: How much do we support the casual user

On 27 March 2018 at 09:26, Vincent Delecroix <20100.delecr...@gmail.com> wrote: > > > On 27/03/2018 10:05, Simon King wrote: > >> Hi Ralf, >> >> On 2018-03-27, Ralf Stephan wrote: >> >>> sage: (2^23+1)/3 >>> 2796203 >>> sage: _.is_prime() >>> False >>> sage: factor(2796203)

[sage-devel] Re: How much do we support the casual user

On Tuesday, March 27, 2018 at 10:08:18 AM UTC+2, Simon King wrote: > > ...since your code is (implicitly!) asking for prime numbers in QQ. > > However, I agree that it is (for most users) unintended behaviour, and > as a corollary to "explicit is better than implicit", we have "implicit > is

[sage-devel] Re: GSoC 2018: mentor application and ideas list

Count me in as well. On Tuesday, January 9, 2018 at 4:33:14 PM UTC+5:30, Harald Schilly wrote: > > Hello everyone. This year's Google Summer of Code started again. Are > we applying again? Who wants to be a mentor for a student? First step > is to get the application done and fill in this

[sage-devel] Re: How much do we support optional packages.

Hi! On 2018-03-25, Volker Braun wrote: > On Sunday, March 25, 2018 at 2:51:46 PM UTC+2, Dima Pasechnik wrote: >> >> one can install autotools on archlinux systemwide >> > > Also, autotools aren't even required to build Sage. > > Whats the point of delaying a release for

Re: [sage-devel] Re: How much do we support the casual user

On 27/03/2018 10:05, Simon King wrote: Hi Ralf, On 2018-03-27, Ralf Stephan wrote: sage: (2^23+1)/3 2796203 sage: _.is_prime() False sage: factor(2796203) 2796203 It turns out that Rational.is_prime does not exist and the fallback gives false answers. My first

Re: [sage-devel] Re: How much do we support the casual user

Ralf, if you use // instead of / then it will do integer division and return integers. sage: for n in prime_range(100): : p = (2^n-(-1)^n)//3 : if p.is_prime(): : print p : 3 11 43 683 2731 43691 174763 2796203 715827883 2932031007403 768614336404564651

[sage-devel] Re: How much do we support the casual user

On 2018-03-27, Simon King wrote: > I know that it is hardly possible to achieve that pasting of printed > output will ALWAYS create a copy of the printed object. However, in > cases where it is easily possible (the real number 1 should print as > 1.0, the rational number 1

[sage-devel] Re: How much do we support the casual user

Hi Ralf, On 2018-03-27, Ralf Stephan wrote: > sage: (2^23+1)/3 > 2796203 > sage: _.is_prime() > False > sage: factor(2796203) > 2796203 > > It turns out that Rational.is_prime does not exist and the fallback gives > false answers. My first association: We should change the

[sage-devel] How much do we support the casual user

Hello, I thought I'd try Sage for a casual computation. I was interested in which numbers of the form (2^n - (-1)^n)/3 are prime. I first tried out n=23: sage: (2^23+1)/3 2796203 sage: _.is_prime() False sage: factor(2796203) 2796203 It turns out that Rational.is_prime does not exist and the