I'm sorry for not being accurate enough to use the correct term for what I'm talking about.
Luckily, you're smart enough to understand my needs, so it seems that I should really go for this new symbolic package, so that we can get something better for symbolic integrals and laplace/inverse laplace transform. Do you think we will have great improvements from that? I am quite frightened from the fact that such a stable and well developed software like maxima still misses this features... how hard would be for SAGE to overcome those? I also want to really stress my hope to further enhance the engineering capabilities of SAGE, and unit of measurements are certainly part of that. Do you think that reusing some code from ScientificPython can be affordable? Probably having the whole package would be too much? About the piecewise functions, I clearly see that those can be useful for reasons (like plotting or something like that), but currently they are not useful at all for things like symbolics and integration. Do any of you consider this an important lack of feature? Someway, I do, and I think that this was the same opinion of the other people previously talking about that (see the discussion linked in my previous posts). I have to say that this seems a quite complicated thing to deal with... Does this kind of feature require a high level mathematical knowledge isn't it? Thank you for the very good work Maurizio On 26 Feb, 23:48, David Joyner <wdjoy...@gmail.com> wrote: > On Thu, Feb 26, 2009 at 5:32 PM, Maurizio <maurizio.gran...@gmail.com> wrote: > > > To the best of my knowledge, the new symbolic (are you referring to > > pynac?) should just be considered as the core of symbolic, and the > > utilities functions should be continue to exist on top of SAGE (or any > > other package actually used, like maxima). > > > Unfortunately, it seems that the inverse laplace function from maxima > > is not the very best, see: > >http://www.math.utexas.edu/pipermail/maxima/2007/008424.html > >http://www.math.utexas.edu/pipermail/maxima/2006/000036.html > > > Is there any sort of representation of piecewise functions in SAGE? > > What about delta function (heaviside) or unit step? These are basics > > for implementing inverse laplace in my opinion. > > The Heaviside function is not the same as the delta function (at least not > in the standard American usage of the term). In any case, piecewise > functions are > inhttp://hg.sagemath.org/sage-main/file/b0aa7ef45b3c/sage/functions/pie... > The delta functional is not implemented as part of the piecewise > package or with the laplace transform code. In general, there is currently > little or no framework in Sage for linear functionals on the vector space of > continuous functions on a given topological space. > > > > > Maxima already has delta() function, and signum() function (that can > > be good to represent the unit step, I don't know if it's already built- > > in maxima function), can we take advantage of that? > >http://www.math.utexas.edu/pipermail/maxima/2006/003249.html > > > There has been a short discussion about that here: > >http://groups.google.com/group/sage-devel/browse_frm/thread/7f33e7001... > > > I know I can seem pretty boring, but I really think that SAGE has a > > great potential, and I would like to enhance its engineering power! As > > it is right now, it still lacks something from that point of view. For > > example (I know, I always go off-topic), has a good units of > > measurement manager ever been included? Also about that you had a long > > discussion, but I don't know the results: > >http://groups.google.com/group/sage-devel/browse_frm/thread/8791448b7... > > > Please, forgive me again for being so annoying > > > Maurizio > > > On 26 Feb, 23:16, Robert Bradshaw <rober...@math.washington.edu> > > wrote: > >> This is outside my area of expertise, so I don't have any immediate > >> pointers, but hopefully the new symbolics will have abilities to do > >> something like this. > > >> - Robert > > >> On Feb 26, 2009, at 1:31 PM, Maurizio wrote: > > >> > Well, that was exactly what I was going to do, but I have no idea how > >> > to implement something like a (symbolic) k-th order derivative, such > >> > that I could then do the limit. Moreover, the derivative seems to be > >> > something close to the core of something like a CAS, so I don't think > >> > I could be able to help for that. > > >> > That's why I was asking for help at least for this derivative part > >> > (and maybe also the limit is not so easy as well). > > >> > I will really try to be helpful, but I still need some support > > >> > Regards > > >> > Maurizio > > >> > On 26 Feb, 21:13, Robert Bradshaw <rober...@math.washington.edu> > >> > wrote: > >> >> On Feb 26, 2009, at 2:49 AM, Maurizio wrote: > > >> >>> Hi all, > > >> >>> what do you think about the inverse_laplace() now present in SAGE? > > >> >>> I am not very satisfied, I am not able to derive the results for > >> >>> even > >> >>> simple functions. > > >> >> It is a simple wrapper around the maxima inverse laplace function. > > >> >>> What I'd like is to get numerical results, so I thought there should > >> >>> have been a way to obtain them, but I didn't find. Can you help me? > > >> >>> In addition, I found on the net the Post's inversion Laplace formula > >> >>> (http://en.wikipedia.org/wiki/Post%27s_inversion_formula). It has > >> >>> been successfully implemented in Maple, here: > >> >>>http://www.mapleprimes.com/blog/alec/numerical-inverse-laplace- > >> >>> transform-0 > > >> >>> I wanted to try this out in SAGE, but the problem seems to be the > >> >>> necessity of doing the k-th derivative of the function, where k is a > >> >>> symbolic variable (that has to go to +Infinity then). I couldn't do > >> >>> that, do you know if that's possible? > > >> >> Not that I am aware of at the moment, but if it would be great if > >> >> someone (for instance you) could implement it and send us a patch. > > >> >> - Robert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
