On Monday, November 3, 2014 4:30:11 AM UTC-8, Sergey Kirpichev wrote: > > On Sun, Nov 02, 2014 at 06:56:31PM -0800, Richard Fateman wrote: > > The Cathedral and the Bazaar essay > > doesn't work if bugs do not become shallow with enough eyes. > > I'm giving up. Probably, I newer can understand why. Esp., if there > is no difference for commercial support and it's obvious that "eyes" can > be of very different qualification. > > > Yes, but in first - you can do anything that can do a client of > > closed-source vendors. And much more (look to the code yourself, > pay > > someone else for support, etc) > > > > In principle. > > No, as a matter of fact. There is a lot of FOSS companies around. > > > Practically, are you willing to pay someone to become an > > expert on (say) Maxima so that sympy can learn from it? > > Practically, it could be much more easy for Maxima experts to > learn SymPy. But yes, I don't see why the quoted above is > impossible: i.e. sponsored work (we have this, at least with > GSoC) or a commercial project, that rely on SymPy (at least I > have some invitations). > > The bad news with SymPy - is that it's derivative could > be closed-source. But I don't think such fork will be useful. > > > > Apparently, Spain universities doesn't matter for the > > > Wolfram Research. > > > > > > That sounds reasonable to me. > > > > Are you sure that any academic institution does matter for Wolfram? > > > > I don;t know what their market looks like, but I am quite sure that > the > > people buying Mathematica for Univ. Calif ask the users at UC, and > for > > the most part they don't are about bug reports enough to cancel > > the re-licensing... > > An how much these users do care about the Mathematica bugs? I see > a lot of people from Cal, who use something different in their work, > incl. the Python and scipy.org stack. >
There is a faculty member at UC (F. Perez) pushing scipy; he invented ipython, I understand. I am not sure how to characterize "a lot of people at Cal". There are 35,000 students. Maybe 1,400 faculty. Perez is a researcher in Brain Imaging, not in computer science or engineering or math. So it may seem like a lot from where you sit. I think it may not seem like so much from where I sit. I do agree with the general premise that it would be nice to improve the quality of scientific computing support from all perspectives, including programming languages. > > i agree. It might be a problem with (say) addition of certain big > > numbers. > > Or with caching, or... > > > This convention was certainly in wide use before 1961. > > Better source? > Maybe check with Bill Gosper, who has done lots of thinking about summation. This is really an "analytic continuation" of the simple indexed sum.. I checked with Gradshteyn and Rhyzik (1960, revised various times later), and they define sum if n<m to be zero. Somewhat to my surprise, but in fairness, I figured I should report it. Summation of Series, edited by Jolley, also 1960-ish (Dover) does not consider this issue. nist's dlmf web site doesn't seem to be concerned with finite summation. disappointing. I think the Knuth etc Concrete Mathematics may have something to say, but I'm not near a copy. Knuth tends to talk about sum over a set, and not the order of indexing. The usual formal definition of a a sum with upper and lower limits, recursively, looks like this: sum(f(i),i,a,a) = f(a) sum(f(i),i,a,b) = f(b) + sum(f(i),i,a,b-1) at least for b>a. Why not allow b>=a?? and therefore sum(f(i),i,a,b) = sum(f(i),i,a,c)+ sum(f(i),i,c+1,b). Now this latter formula can work for c<a. Should work, in my opinion. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/dd72c14e-207e-47b5-9512-cf04ad4a4a85%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
