Re: [sage-devel] Sage code for educational purposes only?
Hi, On Wed, Feb 25, 2015 at 06:55:11PM +0100, Jeroen Demeyer wrote: Hello, Should there be code in Sage which is extremely slow and for educational purposes only? I am talking about eratosthenes() which is just a very slow alternative to prime_range(). I would just remove that code, but maybe people have other opinions... An issue is that names of functions/methods are usually about /what/ is being done, not /how/, hence i am in favor to deprecate eratosthenes() function and move the code as an 'algorithm' option of prime_range(). It should be noticed that the other algorithms depend on pari, hence having at least one self-contained implementation could be of some help, e.g. for consistency testing (and hypothetically for far-future modularization). Recording such self-contained implementations is not only interesting for educational purpose (this is sometimes frustrating to do function?? and only see some calls to an external lib whose source code is not easily available from Sage), but also in a context such as http://wiki.sagemath.org/GSoC/2015#Generic_Dispatcher I remember a discussion with Luca at Orsay during preparation of H2020 stuff, about using Sage as a research tool, where being able to tell Sage i want to rely only on such libs makes sense. So, having a way to record which lib is called in a dispatcher (in particular when no lib is required) is pretty interesting, in particular about reproductibility concerns. Further (and less directly related), i would have proposed to move most *_prime or prime_* functions from the global namespace to methods of the Primes() class (e.g. primes_first_n() vs Primes().__getitem__() or is_prime() vs Primes().__contains__() and so on). This is indeed easier to find primes-related methods, for example, how can i discover the existence of the next_prime() function from the tab completion ? Ciao, Thierry Jeroen. -- 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/d/optout. -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
It is certainly not designed for production work, yet you import things like `LPProblem` in the global namespace ? I will write a patch right now that adds interactive in front of all these classes. See http://trac.sagemath.org/ticket/17867 (needs_review) Nathann -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
Um, can it be perhaps slightly less diminishing? Like education.[tab] or edu.[tab]? E.g. I wrote http://sagemath.org/doc/reference/numerical/sage/numerical/interactive_simplex_method.html which is certainly not designed for production work, but it was quite a bit of work on its own ;-) It is certainly not designed for production work, yet you import things like `LPProblem` in the global namespace ? I will write a patch right now that adds interactive in front of all these classes. Nathann -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
I'm in favor of moving such toys to an educational-library. -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
I really do not see the point of an educational-library if the code will not appear in the documentation. It is precisely the code which is interesting! Vincent -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
On Thu, 26 Feb 2015, Pedro Cruz wrote: +1 for the package educational-algorithms but called educational-packages or educational-library. Yes, '-packages' or '-library' is better name. Hmmm... actually there could be, in principle, three kind of algorithms: 1) Fast ones, that we normally use. 2) Educational, algorithms that made it easy to see some computational proof etc. 3) Most basic and directly from formal definition made algorithms to cross-check fast ones. Usually type 2 and 3 are same thing. Always? -- Jori Mäntysalo
Re: [sage-devel] Sage code for educational purposes only?
+1 for the package educational-algorithms but called educational-packages or educational-library. MathSciNet catalog has the category Mathematics education http://www.ams.org/mathscinet/msc/msc2010.html?t=97-XX being the last topic after all the mathematical edge cutting works. This could inspire an educational-library (this name is maybe more general than just algorithms). Pedro On Thursday, February 26, 2015 at 6:23:36 AM UTC, Jori Mantysalo wrote: On Wed, 25 Feb 2015, Jeroen Demeyer wrote: Should there be code in Sage which is extremely slow and for educational purposes only? As an additional package educational-algorithms? -- Jori Mäntysalo -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
Le mercredi 25 février 2015 20:56:06 UTC+1, kcrisman a écrit : Who on earth thinks that the Sieve of Eratosthenes is designed for modern production work??? Me. I´m using it for the ithprime function in Giac. ithprime(70) returns 10570841 in 0.07 second while in sage prime_range(1,10570841) takes about the same time (0.08s) to compute (much more to display). -- 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/d/optout.
[sage-devel] Sage code for educational purposes only?
Hello, Should there be code in Sage which is extremely slow and for educational purposes only? I am talking about eratosthenes() which is just a very slow alternative to prime_range(). I would just remove that code, but maybe people have other opinions... Jeroen. -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
On 02/25/2015 02:10 PM, William Stein wrote: toys.eratosthenes() or possibly eratosthenes_toy()... In this case, the name refers to the implementation, not the functionality, so I don't think it's a big deal. It's not a prime number routine that just happens to be slow -- it's the sieve of Eratosthenes, running as fast as it can. Any other implementation will be just as slow. -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
I also feel like we should remove it from the source code. The purpose of eratosthene is very different from what Andrey pointed out with his module about the simplex method. The function eratosthene is just an illustration of how you code a nice Python function. While the simplex module is more of exploration and experimentation of an algorithm. For eratosthene you need to read the code while for the simplex module you just experiment the functionalities of the object. So I propose to move eratosthene from the source to the documentation (where is another question). And, as William pointed out, it would be a good example to illustrate the power of Cython. And I definitely think that Andrey simplex stuff has its place inside the source. Vincent -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
On Wed, Feb 25, 2015 at 2:10 PM, William Stein wst...@gmail.com wrote: On Wed, Feb 25, 2015 at 10:15 AM, Michael Orlitzky mich...@orlitzky.com wrote: ... I think it's best to name any functionality that is is extremely slow and for educational purposes explicitly with toy somewhere in the name. If you do: sage: search_src(toy) you'll see this convention often in sage. I would be for deprecating eratosthenes() and replacing it by something like toys.eratosthenes() or possibly eratosthenes_toy()... I like the idea of a toys.[tab] that gathers together toy implementations... +1 ... -- 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/d/optout. -- William (http://wstein.org) -- 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/d/optout. -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
Um, can it be perhaps slightly less diminishing? Like education.[tab] or edu.[tab]? E.g. I wrote http://sagemath.org/doc/reference/numerical/sage/numerical/interactive_simplex_method.html which is certainly not designed for production work, but it was quite a bit of work on its own ;-) I am also not a fan of prefixing/suffixing all names with something or grouping it into a special folder - toy number theory should still go into number theory tree and included into its documentation, just perhaps exported through a dedicated module somewhere. Andrey On Wednesday, 25 February 2015 12:24:41 UTC-7, David Joyner wrote: On Wed, Feb 25, 2015 at 2:10 PM, William Stein wst...@gmail.com javascript: wrote: On Wed, Feb 25, 2015 at 10:15 AM, Michael Orlitzky mic...@orlitzky.com javascript: wrote: ... I think it's best to name any functionality that is is extremely slow and for educational purposes explicitly with toy somewhere in the name. If you do: sage: search_src(toy) you'll see this convention often in sage. I would be for deprecating eratosthenes() and replacing it by something like toys.eratosthenes() or possibly eratosthenes_toy()... I like the idea of a toys.[tab] that gathers together toy implementations... +1 ... -- 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+...@googlegroups.com javascript:. To post to this group, send email to sage-...@googlegroups.com javascript:. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout. -- William (http://wstein.org) -- 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+...@googlegroups.com javascript:. To post to this group, send email to sage-...@googlegroups.com javascript:. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout. -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
Um, can it be perhaps slightly less diminishing? Like education.[tab] or edu.[tab]? We have a number of crypto examples of toy things, and David J. long ago wrote quite a few things like Euler's method and so forth. It is very, very worthwhile (if for no other reason than to have opportunities for people to understand how to code math!). I am also not a fan of prefixing/suffixing all names with something or grouping it into a special folder - toy number theory should still go into number theory tree and included into its documentation, just perhaps exported through a dedicated module somewhere. I don't think we need toy.[tab] or number_theory.toy.[tab] or anything. Who on earth thinks that the Sieve of Eratosthenes is designed for modern production work??? Or Euler's Method (well, I'm not a numerical analyst, so maybe, but I assume other integration is more prominent). In some cases of course this is useful to prefix, and we have http://www.sagemath.org/doc/reference/polynomial_rings/sage/rings/polynomial/toy_buchberger.html and things like that for such cases. If the documentation of any given method says it's for educational purposes only - and there are a number of those - then that seems fine to me. - 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
On Wed, Feb 25, 2015 at 11:57 AM, Michael Orlitzky mich...@orlitzky.com wrote: On 02/25/2015 02:10 PM, William Stein wrote: toys.eratosthenes() or possibly eratosthenes_toy()... In this case, the name refers to the implementation, not the functionality, so I don't think it's a big deal. It's not a prime number routine that just happens to be slow -- it's the sieve of Eratosthenes, running as fast as it can. Any other implementation will be just as slow. I'm not sure I agree. This eratosthenes function is pure Python code. It would probably be 100 times faster if rewritten in Cython using int's or long's. In fact, this is (more or less) the canonical first example of a function that benefits directly from being compiled rather than pure Python -- it's the first example on the Pyrex page: http://www.cosc.canterbury.ac.nz/greg.ewing/python/Pyrex/ That you would think it's the sieve of Eratosthenes, running as fast as it can. Any other implementation will be just as slow is in fact to me a very strong argument for why it *should* have toy in the name. Since if it did, it's highly unlikely you would think it is running as fast as it can. William -- William (http://wstein.org) -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
On Wed, Feb 25, 2015 at 10:15 AM, Michael Orlitzky mich...@orlitzky.com wrote: On 02/25/2015 12:55 PM, Jeroen Demeyer wrote: Hello, Should there be code in Sage which is extremely slow and for educational purposes only? I am talking about eratosthenes() which is just a very slow alternative to prime_range(). I would just remove that code, but maybe people have other opinions... I also agree it is OK to have such *code*. However, to have it just there without a name that strongly emphasizes its toy nature is very bad. People often think that if f is a function defined in a respectable math software system (Magma or Sage), then the performance of f(n) is at least reasonable. I think it's best to name any functionality that is is extremely slow and for educational purposes explicitly with toy somewhere in the name. If you do: sage: search_src(toy) you'll see this convention often in sage. I would be for deprecating eratosthenes() and replacing it by something like toys.eratosthenes() or possibly eratosthenes_toy()... I like the idea of a toys.[tab] that gathers together toy implementations... It's nice to leave in code like this and use it as part of the test suite. It would be easy to check that the sieve of Eratosthenes is correct, but prime_range() is a long chain of dark magic to me. A good test would be that they agree on the primes below (say) 1,000: sage: eratosthenes(1000) == prime_range(1000) True There are some tests for prime_range() already, e.g. sage: L = prime_range(25000,250) sage: len(L) 180310 but who knows if the results are correct. -- 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/d/optout. -- William (http://wstein.org) -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
On 02/25/2015 12:55 PM, Jeroen Demeyer wrote: Hello, Should there be code in Sage which is extremely slow and for educational purposes only? I am talking about eratosthenes() which is just a very slow alternative to prime_range(). I would just remove that code, but maybe people have other opinions... It's nice to leave in code like this and use it as part of the test suite. It would be easy to check that the sieve of Eratosthenes is correct, but prime_range() is a long chain of dark magic to me. A good test would be that they agree on the primes below (say) 1,000: sage: eratosthenes(1000) == prime_range(1000) True There are some tests for prime_range() already, e.g. sage: L = prime_range(25000,250) sage: len(L) 180310 but who knows if the results are correct. -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
On 02/25/2015 03:04 PM, William Stein wrote: Any other implementation will be just as slow. I'm not sure I agree. This eratosthenes function is pure Python code. It would probably be 100 times faster if rewritten in Cython using int's or long's. In fact, this is (more or less) the canonical first example of a function that benefits directly from being compiled rather than pure Python -- it's the first example on the Pyrex page: http://www.cosc.canterbury.ac.nz/greg.ewing/python/Pyrex/ That you would think it's the sieve of Eratosthenes, running as fast as it can. Any other implementation will be just as slow is in fact to me a very strong argument for why it *should* have toy in the name. Since if it did, it's highly unlikely you would think it is running as fast as it can. Surely we aren't going to start naming things toy just because they're written in Python? I tested in Cython and was going to post numbers, but looking back, you only suggested it would be 100 times faster. The speedup is actually better than that (looks sublinear) -- I just don't consider a factor of 100 on a silly algorithm to be a big difference. You still hit a running time of (1/100)*forever pretty quickly. -- 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/d/optout.
Re: [sage-devel] Sage code for educational purposes only?
On Wed, 25 Feb 2015, Jeroen Demeyer wrote: Should there be code in Sage which is extremely slow and for educational purposes only? As an additional package educational-algorithms? -- Jori Mäntysalo
