On Friday, 22 August 2014 11:49:20 UTC+2, Pierre wrote: > > I thought we would have another argument about real numbers this morning, > but I see the topic has changed back to Julia. And I have to say that I > find the Nemo project very interesting, in spite of the over-aggressive > publicity it is receiving here. >
I wasn't going to mention it here at all. But I decided that on the tail end of a very long thread it wouldn't hurt much. It seems like a lot more people were reading the thread than I thought. I don't intend to plug Nemo on sage-devel! > > You don't often get to see a new piece of software in its infancy, with > the opportunity to request features from the developpers so early on. So > here's a suggestion for Bill Hart; you write: > > >Nemo is Julia, in the same way as Sage is Python > > I'm not sure if I fully understand this, but I'm afraid I do. And I don't > think it's a good decision. Let me explain. > > I'm very jealous of some colleagues in numerical analysis here at my > university whose ecosystem is ipython+numpy+matplotlib (pretty much, i may > forget something). All three can be installed with easy_install at the > prompt; it's modular (don't load matplotlib if you don't plan to plot); > it's lightweight. > > why shouldn't nemo by a Julia module that people load explicitly? > At the moment this is possible. But the bignum issue is really too much inconsistency for me. It's not just that, but the way the operators are defined on the Int's is also not what an algebraist wants. 1/2 returns 0.5 instead of 1/2. And div(7//2, 1//3) returns 10. Go figure. You can't have consistent computer algebra when small integer literals behave differently to bigger ones. It just doesn't work. This will be an issue when it comes to p-adics for example: a = 1 + 2*65537 + 3^65537^2 + 11*65537^3 + 13*65537^4 + 12345*65537^5 + O(65537^6) will return who knows what. Certainly not what you entered. Factorisations of number a = 2*3*5^2*17*71*65537*123456543234565433489*3249861239487619238746032103420132947612384712340813246341 will return who knows what. Certainly not what you entered. This is just not a tolerable situation for computer algebra. So alas, the input has to be changed to bignum by default. It's also a pain in the neck to take output from one system, such as Pari/GP and cut and paste a long polynomial, having to put ZZ(...) around every bignum. It's just not practical. > There are many good reasons why Sage cannot just be a module for Python. > However I remember conversations in this forum years ago when people were > musing about how great it would be if, by some miracle, Sage could indeed > be a (collection of) module(s): it would be so simple and healthy. (Wasn't > the Purple Sage project started with this "simplicity" in mind?) And it > would be much easier to explain to people what Sage is. This may be a minor > point, but if you've followed the conversation on reddit a few hours ago: > > > http://www.reddit.com/r/math/comments/2e3qla/william_stein_says_sage_has_overall_failed/ > I did. > > > then you will see how many misconceptions people have about Sage, and how > scary the technology appears to some. > > Again there are very good reasons why Sage is what it is, but I see no > reason why Nemo should be compelled to take over Julia like Sage has had to > take over Python. You even say that no preparsing is needed! I'm not sure > if, for example, you want to insist that integer constants be interpreted > automatically as elements of ZZ. It seems to me a minor nuisance to have to > write a few extra ZZ's, if in exchange the system can be that much simpler. > I'm wondering what other people think. > I wish it were that simple. It might be possible to have Julia load in bare-module mode and still make Nemo available as a Julia Pkg though. I'll talk to the Julia developers about it. It would certainly be great if that were possible. > > Oh, and I ain't trying Nemo myself until installation is along the lines > of "julia --easy_install nemo", sorry... I would love to try it on > SageMathCloud if it's available. > Yeah me too. Bill. > > best, > Pierre > > > > > > > > -- 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.
