[sage-support] Re: [sage-cloud]: abs return negative value
Thank you! I understand this means that in Sage 6.8 it is fixed, am I right? If so, I have to wait for an update of Sage on cloud.sagemath.com (at the moment is 6.7). Can I import Pynac-0.4.1(or Pynac-0.3.9.1) in Sage 6.7 on the cloud? My best regards. On Tuesday, July 7, 2015 at 7:32:34 AM UTC+2, Ralf Stephan wrote: > > Fixed in Pynac-0.4.1, backport in Pynac-0.3.9.1 (it was there in 0.3.8 > actually already but review is lagging) > > http://trac.sagemath.org/ticket/18537 > > Regards, > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
[sage-support] [sage-cloud]: abs return negative value
On cloud.sagemath.com, on a brand new notebook, if I evaluate abs(-2^(1/2)) the result is -sqrt(2) Expected result: sqrt(2) or abs(-sqrt(2)) In my local installation (SageMath Version 6.6, Release Date: 2015-04-14, Ubuntu 15.04) it works fine. Any idea where could be the problem? Thanks! -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
[sage-support] Fwd: Console and editor in the notebook
Hi all, I'm forwarding this message to sage-support as well, because I could get no support on sage-notebook. I hope you don't consider this as spam, I would just like to hear some comments. Eventually I'll try on sage-devel :) Thanks Maurizio -- Forwarded message -- From: Maurizio Date: 3 Ago, 19:26 Subject: Console and editor in the notebook To: sage-notebook Hi all, I'd like to kindly ask for some support. I'd like to try an experiment with the notebook. My aim is to create a new python function, something like: file_editor(filename) which would open a new browser windows (like a popup), which contains two main elements which are fixed in the html layout: 1) a file editor, containing the filename specified (let's say, a script named "my_script.sage") which is opened, or created if not existing, into the DATA folder of the worksheet; it provides syntax highlighting and (possibly) tab-completion 2) an interactive console, composed of a one-line input and some lines of output, like if it were a live sage session opened. it should also provide facilities like tab-completion. That console should be attached to the same SAGE session opened in the worksheet where the "file_editor" command has been called, so have the same globals, etc.. The problem is: I know how to open a popup, and I used the edit mode of the file attached to the notebook as a template for having a box with syntax highlighting using codemirror (so the necessary javascript library is already there). I don't know how to create a simil-console in the way I descripted it: I would like to keep it quite simple, so I don't know if it is possible to create something like a single-line cell, and how to send the input to the SAGE console and to get the result back. Moreover, I don't know how to reach the same SAGE session that is operating in the calling worksheet. Can you help me with this? I had a look at the notebook_lib.js file, but I am not sure which methods to focus on. Regarding the editor, where do I find the "save" methods already present in the notebook? Moreover, I'd like to have a couple of buttons with the editor (I know how to make a toolbar, by the way), which are: 1) save file (shortcut F5) 2) save file and run it (shortcut, maybe CTRL+F5) 3) run selected code in the console (shortcut F9) ... something similar to this Finally, I'm considering to also show the output of the console (or that of the script), as the output of the cell in the original worksheet. Thanks for any kind of support. If you can point me to something similar already existing, or to some specific documentation, I'll be happy. I already had a look athttp://www.sagemath.org/doc/reference/sagenb/simple/twist.html I'm wondering if there's some similar doc for existing javascript functions. Regards Maurizio -- 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 URL: http://www.sagemath.org
[sage-support] is animate so slow?
hi all,
I was trying to animate a plot, with only few frames (50).
I get a very slow animate:
from numpy import linspace
t_vec = linspace(0,Tn,50)
L = Graphics()
v = []
tp = []
Xp = []
Yp = []
for tn in t_vec:
tp.append(tn)
Xp.append(X.subs(val_dict).subs(t = tn))
Yp.append(Y.subs(val_dict).subs(t = tn))
L += list_plot(zip(Xp,Yp), plotjoined = True)
v.append(L)
Xmin = min(Xp)
Xmax = max(Xp)
Ymin = min(Yp)
Ymax = max(Yp)
a = animate(v, xmin = Xmin, xmax = Xmax, ymin = Ymin, ymax = Ymax)
timeit('a.show()', repeat = 1)
5 loops, best of 1: 12 s per loop
is this expected?
thanks
maurizio
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[sage-support] Re: evaluating numerically a function expression
is there any form of pattern matching in sage? that should be the basic tool to do something like you mentioned, is it correct? Maurizio On 25 Lug, 11:35, Renato wrote: > On Sat, 24 Jul 2010 11:03:45 -0700 > > > > Jason Grout wrote: > > On 7/24/10 4:38 AM, Renato wrote: > > > Hi, this seems very basic, but I wasn't able to figure it out. > > > Let's say I have a function: > > > > sage: f(t) > > > -4*(5*sqrt(2)*cos(1/2*sqrt(2)*sqrt(5)) - > > > 2*sqrt(5)*sin(1/2*sqrt(2)*sqrt(5)))*sin(1/2*sqrt(5)*t)/(sqrt(5)*sin(1/2*sqrt(2)*sqrt(5))^2 > > > + sqrt(5)*cos(1/2*sqrt(2)*sqrt(5))^2) + > > > 4*(5*sqrt(2)*sin(1/2*sqrt(2)*sqrt(5)) + > > > 2*sqrt(5)*cos(1/2*sqrt(2)*sqrt(5)))*cos(1/2*sqrt(5)*t)/(sqrt(5)*sin(1/2*sqrt(2)*sqrt(5))^2 > > > + sqrt(5)*cos(1/2*sqrt(2)*sqrt(5))^2) - 8 > > > > how do I tell sage to evaluate numerically everything but sin(), > > > cos() and t? I.e. I know this function is in the form > > > > f(t) = a*sin(b*t) + c*cos(d*t) > > > > can I tell sage to put it in this form, evaluating numerically a,b,c > > > and d? > > > > kind regards > > > renato > > > It looks like there is also a -8 at the end: > > ah yes, you're right. > > > sage: f(t)=-4*(5*sqrt(2)*cos(1/2*sqrt(2)*sqrt(5)) > > -2*sqrt(5)*sin(1/2*sqrt(2)*sqrt(5)))*sin(1/2*sqrt(5)*t)/(sqrt(5)*sin(1/2*sqrt(2)*sqrt(5))^2+ > > sqrt(5)*cos(1/2*sqrt(2)*sqrt(5))^2) > > +4*(5*sqrt(2)*sin(1/2*sqrt(2)*sqrt(5)) > > +2*sqrt(5)*cos(1/2*sqrt(2)*sqrt(5)))*cos(1/2*sqrt(5)*t)/(sqrt(5)*sin(1/2*sqrt(2)*sqrt(5))^2+ > > sqrt(5)*cos(1/2*sqrt(2)*sqrt(5))^2) - 8 > > > sage: f.subs_expr(sqrt(5)==sqrt(5).n(),sqrt(2)==sqrt(2).n()) > > t |--> 8.13039327042996*sin(1.11803398874989*t) + > > 12.5656955743861*cos(1.11803398874989*t) - 8 > > > Basically, I used subs_expr to subsititute in numeric values for the > > square roots. > > thanks :) > > > Question to the community at large: > > > It seems like f.n() should do the above (evaluate what it can > > numerically, leave the variables alone). But this doesn't work: > > yes it would be nice indeed to have a more general way of doing this. > > regards > renato -- 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 URL: http://www.sagemath.org
[sage-support] include another worksheet
hi all! I have a simple question, sorry if I could have found the answer somewhere else What should I do if I want to include another notebook worksheet at the beginning of a new worksheet? For example, if I have some other functions or values or variables there I want to reuse. Something like "load" or "import", what can I do? thanks Maurizio -- 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 URL: http://www.sagemath.org
[sage-support] Acrobat Reader is required?
Hi all, while using the 4.1.1 notebook, I noticed this has been displayed in the sage terminal sh: acroread: not found Is that acroread is required for any feature? I'm actually using evince in Ubuntu, and I don't feel the necessity to install it. Maybe it could be useful to add support for other pdf viewers? Thanks --~--~-~--~~~---~--~~ 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 URL: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: Matlab like Workspace for Sage
Do you know sage-mode? When I asked for the same, that was showed to me. Basically, you can plugin SAGE into Emacs, and what you get is Matlab like Workspace GUI for SAGE! I mean, you have: - one or more file editors, for long scripts which doesn't necessarily take advantage of having more cells - one history powered command line which is always accessible, and that can run the script you are working on immediately - syntax highlighting (missing in the notebook) and tabbing support!! - something else I don't recall now... It misses minor things like workspace browser, or filesystem browser, or history browser, but I don't think that makes a huge difference! Moreover, I think Emacs can be not that hard to start with (at the beginning, it just looks like a normal editor for programmers), and can be pretty easy to learn some powerful functionalities (that are not necessary to be productive, at the same time). I feel it is a good thing to work with in the meantime, of course while we wait for a Matlab-like GUI in the notebook :) (which would still probably be even better!) Maurizio On Sep 29, 8:53 pm, William Stein wrote: > On Tue, Sep 29, 2009 at 11:48 AM, Mike Hansen wrote: > > > Hello, > > > On Wed, Sep 30, 2009 at 1:34 AM, Umut wrote: > > >> Hi, > >> is there anyone planning a Matlab like Workspace GUI for Sage? > > > I don't know of anyone specifically. However, there is Spyder ( > >http://code.google.com/p/spyderlib/) which probably wouldn't be too > > difficult to hook up to Sage if someone put in some effort. > > It would also probably not be too difficult to make a different "mode" > for the Sage notebook that looked just like Matlab. Does that sound > useful? > > William --~--~-~--~~~---~--~~ 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 URL: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: How can I incorporate ready made graphics?
Maybe change ImageName.png with the name of the image you uploaded... By the way be careful with filenames with spaces in between: I have had annoying troubles in dealing with spaces rather than "%20"s (which is the way spaces are represented in URLs). Hope that helps. Maurizio On 28 Ago, 12:14, Ling Kah Jai wrote: > What is wrong? I cannot get it working by inputting the command in a > cell: > print "" % DATA > > On Aug 28, 1:44 pm, Robert Bradshaw > wrote: > > > > > Oh, you want to put them into a notebook worksheet. You can also do > > this by adding it to the data (there's an "upload data" option) and > > then doing > > > print "" % DATA > > > - 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 -~--~~~~--~~--~--~---
[sage-support] Re: Sage & Unum
thank you very much for sharing this! maurizio On 15 Lug, 21:47, dw wrote: > I was able to find a solution to my problem. If anyone else wants to > do the same thing, I added the following function to unum/__init_.py. > > def round(self, sig_fig): > ''' returns a string representation of the number w/ units > showing only the set number of significant digits > ''' > return '%s %s' % (round(self.asNumber(),sig_fig), self.strUnit > ()) > > This just gives you a method to print the number of desired digits. > > On Jul 14, 12:08 pm, dw wrote: > > > I've been evaluating Sage for engineering applications. The one > > missing part, which after reading this forum I've realized is > > currently being worked on, is unit support. The best solution I've > > been able to use so far is Unum. It works well in my application, but > > in the notebook I'd like to be able to limit the number of digits > > shown. I'd previously been using print '%.3f" to set the display, but > > it doesn't work with Unum numbers. I'm sure this would be better > > asked in an Unum forum, but I haven't found one and it seems a few > > people here have used the package. > > Also, on a more general note. Can you set the significant digits > > displayed throughout a notebook somehow? > > > Thanks. --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
I totally agree, but unfortunately it seems there are not so many people involved in the development of SAGE, focused on these topics. Thank you for your comment Regards Maurizio On Jun 24, 9:26 am, petrush wrote: > I would just like to comment about the interest in units, that I think > unit support for SAGE would be highly appreciated for a large audience > dealing with all kind of engineering/physics/etc calculations. It is > not sure that this group is following the development in SAGE today, > since it's known mainly as a mathematics tool and much of these > calculations are done in industry. > > As far as I know, today the only low-entry-level tool that does this > is mathcad, which is commercial. > > So, your efforts in this area will be highly appreciated, by me and > others... :) --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
On 17 Giu, 09:24, Robert Bradshaw
wrote:
> Thanks for the wiki and summary. In my (brief) perusal of the
> options, Unum sounds like the best fit to me too.
>
I am glad I can give something to this community, I hope this has been
valuable to somebody.
> On Jun 15, 2009, at 3:27 AM, William Stein wrote:
>
> > There is also the fact that Sage has rings, elements, parents, a
> > coercion model, etc. which might throw a monkey wrench into everything
> > (I don't know).
>
> I'm hoping it's able to store the "numeric" part as a black box, and
> just multiplies it by constants to convert. Of course, I'm not sure
> if everything would quickly be reduced to 53-bit floating point
> results precision...
>
Thank you for investigating this!!
> sage: var('x,y')
> (x, y)
> sage: (x * unum.units.MILE) / (y * unum.units.S)
> x/y [mile/s]
> sage: (x+90) * unum.units.MIN + (x+pi) * unum.units.H
> pi + 1.016667*x + 1.50 [h]
>
> sage: R. = QQ[[]]
> sage: foo = (1/(t+1)) * unum.units.KG; foo
> 1.0 - 1.0*t + 1.0*t^2 - 1.0*t^3 + 1.0*t^4 - 1.0*t^5 + 1.0*t^6 -
> 1.0*t^7 + 1.0*t^8 - 1.0*t^9 + 1.0*t^10 - 1.0*t^11 + 1.0*t^12 -
> 1.0*t^13 + 1.0*t^14 - 1.0*t^15 + 1.0*t^16 - 1.0*t^17 + 1.0*t^18 -
> 1.0*t^19 + O(t^20) [kg]
> sage: getattr(foo, 'as')(unum.units.TON)
> 0.001 - 0.001*t + 0.001*t^2 - 0.001*t^3 + 0.001*t^4 - 0.001*t^5 +
> 0.001*t^6 - 0.001*t^7 + 0.001*t^8 - 0.001*t^9 + 0.001*t^10 -
> 0.001*t^11 + 0.001*t^12 - 0.001*t^13 + 0.001*t^14 - 0.001*t^15 +
> 0.001*t^16 - 0.001*t^17 + 0.001*t^18 - 0.001*t^19 + O(t^20) [t]
>
> Not bad.
>
> - Robert
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[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
Very interesting... so how would be the best way to do this with symbolics in SAGE? I think the recent switch to pynac requires the community some time to learn how to use it. Nonetheless, I sent an email to the author of Unum, so he could at least point out some suggestions, if not directly help to, write some code taking advantage of SAGE capabilities, which he may really benefit. Thanks for the comment Regards Maurizio On 15 Giu, 20:30, Robert Dodier wrote: > On Jun 15, 4:24 am, Maurizio wrote: > > > precisely, basic units (as meter, second, etc) are, by definition, > > terminal unums (without references); derived units (as Newton, Joule, > > etc) have a dictionary with, as keys, unums representing basic/derived > > units, and, as values, their exponents; finally, any quantity may be > > derived with the same idea. > > Well, I think this is an example of an operation (and it's pretty > important to the unit conversion stuff) that could be simplified > quite a bit by exploiting Sage's capabilities instead of trying > to bolt on an existing package. > > If you had a list of equations of derived units in terms of basic > units, you could immediately compute a conversion factor > for two derived units. So the question is how to get such a list. > > Unit conversions are conveniently expressed by equations > like foo = bar^m * baz^n. Any such equation defines a derived > unit; basic units or other derived units might appear on the right. > > To get conversions to base units, just solve all the equations > for all the derived units. (It's convenient to take logarithms > so the equations are linear.) Then you have every derived unit > expressed in terms of basic units only. When new conversions > are defined, just append the new equations and solve it again. > > Symbolic operations (representing equations, solving > equations, log and exp, substitution or evaluation) make that > construction very simple. The whole business with building > a hash table or a graph or whatever is just a workaround for > the lack of symbolic operations. > > best > > Robert Dodier --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
I am wondering whether somebody contacted the author. Let me cite him (everything is better explained in the wiki): - I have another idea for further development, which is more technical. It is to remove the unit dictionary stored as Unum's class attributes (which is the cornerstone of the current design !). Currently, the unit symbol strings are used as keys for this dictionary; numerous dictionary lookups may occur at unit normalization or unification. The idea now is that each unum contains direct references to other unums representing its inner units. More precisely, basic units (as meter, second, etc) are, by definition, terminal unums (without references); derived units (as Newton, Joule, etc) have a dictionary with, as keys, unums representing basic/derived units, and, as values, their exponents; finally, any quantity may be derived with the same idea. The big picture at the end is that all quantities, units and conversion rules boils down to a single connected graph where each node is a unum. This redesign should save a lot in time and memory consumption. It requires however to rewrite almost all Unum's methods. I wrote a small prototype to validate the concept, with promising results. This is coming from the last entry of Unum Diary ( http://home.scarlet.be/be052320/Unum_diary.html ). Do you think could be possible for us to get the prototype from him, and to adapt it to work with SAGE, in order to take advantage of his experience in designing a Units of Measurement package, and at the same time to get the chance to make it work well with SAGE in the early phase of its development? The result could be the same to make Quantities work with SAGE, but I am doubtful if it would take less time to make Quantities work well in SAGE, rather than adopt this Unum (let's say 5.0 alpha) and possibly invite the original author to cooperate with us, if he's willing to and has some spare time. Regards Maurizio On Jun 15, 12:10 am, Maurizio wrote: > I added some comments to the wiki about Quantities as well. > > From the point of view of the code, I can give my impression, but I'm > not experienced in programming. > Unum looks simple and understandable. > Quantities looks more complex, and even finding the right way to look > at is difficult for me. Anyway, this could also mean that the package > is refined and designed from an experienced programmer, so this could > be a pro. Anyway, that would certainly prevent people like me to work > on it :) > > Regards > > Maurizio > > On 14 Giu, 23:38, Maurizio wrote: > > > > "as" is going to be a keyword in Python 2.6 so this will actually have > > > to be changed. It makes sense to do it before it's in Sage since it > > > will break code. > > > Yes, indeed that's even coming out when executing its own test suite: > > Python is warning that as is a keyword in 2.6. > > > > > Note that the license is GPLv2, not GPLv2+, > > > >http://home.scarlet.be/be052320/license.txt > > > > Maybe someone should contact the package author about that > > > > before a definite move is made? > > > > All of the license statements on the source code itself are GPLv2+. > > > > There are also a few changes that should to be done such as something like > > > > try: > > > from sage.all import Integer > > > ONE = Integer(1) > > > except ImportError: > > > ONE = 1.0 > > > > so that it plays nicer with exact arithmetic. > > > > --Mike > > > William, as I stated in the wiki, I'm gaining interest toward Unum. I > > was going to include some examples of Quantites in SAGE as well (for > > "par condicio", as they say in Italy). > > > I don't know what about contacting the author or modifying the code, > > but please consider also the effort needed to make it work with the > > non-arithmetic functions: > > 1. trigonometric > > 2. integration, derivation > > 3. possibly compatibility with symbolics? > > > I would consider point (1) the minimum necessary to avoid making Unum > > (or any other units package) inclusion meaningless. > > > Thanks for the interest, anyway > > > Regards > > > Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
I added some comments to the wiki about Quantities as well. >From the point of view of the code, I can give my impression, but I'm not experienced in programming. Unum looks simple and understandable. Quantities looks more complex, and even finding the right way to look at is difficult for me. Anyway, this could also mean that the package is refined and designed from an experienced programmer, so this could be a pro. Anyway, that would certainly prevent people like me to work on it :) Regards Maurizio On 14 Giu, 23:38, Maurizio wrote: > > "as" is going to be a keyword in Python 2.6 so this will actually have > > to be changed. It makes sense to do it before it's in Sage since it > > will break code. > > Yes, indeed that's even coming out when executing its own test suite: > Python is warning that as is a keyword in 2.6. > > > > > > Note that the license is GPLv2, not GPLv2+, > > >http://home.scarlet.be/be052320/license.txt > > > Maybe someone should contact the package author about that > > > before a definite move is made? > > > All of the license statements on the source code itself are GPLv2+. > > > There are also a few changes that should to be done such as something like > > > try: > > from sage.all import Integer > > ONE = Integer(1) > > except ImportError: > > ONE = 1.0 > > > so that it plays nicer with exact arithmetic. > > > --Mike > > William, as I stated in the wiki, I'm gaining interest toward Unum. I > was going to include some examples of Quantites in SAGE as well (for > "par condicio", as they say in Italy). > > I don't know what about contacting the author or modifying the code, > but please consider also the effort needed to make it work with the > non-arithmetic functions: > 1. trigonometric > 2. integration, derivation > 3. possibly compatibility with symbolics? > > I would consider point (1) the minimum necessary to avoid making Unum > (or any other units package) inclusion meaningless. > > Thanks for the interest, anyway > > Regards > > Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
> "as" is going to be a keyword in Python 2.6 so this will actually have > to be changed. It makes sense to do it before it's in Sage since it > will break code. > Yes, indeed that's even coming out when executing its own test suite: Python is warning that as is a keyword in 2.6. > > Note that the license is GPLv2, not GPLv2+, > >http://home.scarlet.be/be052320/license.txt > > Maybe someone should contact the package author about that > > before a definite move is made? > > All of the license statements on the source code itself are GPLv2+. > > There are also a few changes that should to be done such as something like > > try: > from sage.all import Integer > ONE = Integer(1) > except ImportError: > ONE = 1.0 > > so that it plays nicer with exact arithmetic. > > --Mike William, as I stated in the wiki, I'm gaining interest toward Unum. I was going to include some examples of Quantites in SAGE as well (for "par condicio", as they say in Italy). I don't know what about contacting the author or modifying the code, but please consider also the effort needed to make it work with the non-arithmetic functions: 1. trigonometric 2. integration, derivation 3. possibly compatibility with symbolics? I would consider point (1) the minimum necessary to avoid making Unum (or any other units package) inclusion meaningless. Thanks for the interest, anyway Regards Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
William, David, thanks for your help. I am really surprised by how dumb should I have been yesterday. Today everything looks easy :) Anyway, I updated the wiki page since I successfully installed Unum in SAGE. You can see the (pretty encouraging) results there: http://wiki.sagemath.org/Unit%20of%20Measurement Any other comment and suggestion is greatly appreciated. Regards Maurizio On 14 Giu, 15:27, David Joyner wrote: > Maurizio: > I'm not sure when you createdhttp://wiki.sagemath.org/Unit%20of%20Measurement > but a "secret question" has been added to the wiki which you have to > answer for each > edit. The answer to the question is (hopefully) pretty obvious. I > think the question > appears near the top of the page after each edit. If you forget, or > don't notice that > question is there, your edits will not be applied. > > On Sat, Jun 13, 2009 at 7:44 PM, Maurizio wrote: > > I created the wiki page for this in SEP: > > >http://wiki.sagemath.org/SEP > > > Unfortunately, it seems I don't have the rights to modify the page I > > created. I attach here that page, can somebody upload it? > > > Any comment is greatly appreciated. > > > Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
Well, actually SEP was containing a list of links to wiki pages of proposals. I'm sorry but I have been misunderstood: I meant to say that in SEP (Sage Enhancement Proposal) there was the link to the wiki page I created: Units of Measurement. In fact, I didn't mean to substitute that SEP page, but to just fill the newly created page. Can you restore the old SEP page, and put the content I sent into the Unit of Measurement subpage, that is linked by SEP? Thanks Maurizio On 14 Giu, 09:09, William Stein wrote: > On Sun, Jun 14, 2009 at 1:44 AM, Maurizio wrote: > > I created the wiki page for this in SEP: > > >http://wiki.sagemath.org/SEP > > > Unfortunately, it seems I don't have the rights to modify the page I > > created. > > I've never heard of that in 3 years of running that wiki. I don't > know how you setup things so you suddenly can't modify your own wiki > page. > > > I attach here that page, can somebody upload it? > > Done. > > > > > Any comment is greatly appreciated. > > > Maurizio > > -- > William Stein > Associate Professor of Mathematics > University of Washingtonhttp://wstein.org --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Dimensional Analysis or Unit Conversion capability?
I created the wiki page for this in SEP: http://wiki.sagemath.org/SEP Unfortunately, it seems I don't have the rights to modify the page I created. I attach here that page, can somebody upload it? Any comment is greatly appreciated. Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~--- Unit of Measurement.wiki Description: Binary data
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
Hi > I'm going to suggest that interested parties just write a new > package for Sage, after reviewing existing packages, instead > of trying to bolt one of the existing packages onto Sage. I have honestly taken this into account, but there are a couple of cons: - nobody is volunteering, so the amount of work-time seems very limited - I don't like to reinvent the wheel, that's why I like SAGE so much - I have very limited experience about Python programming (especially classes and stuff like that) - I would like to take advantage of others' experience about designing a package like that > > Unit conversion and dimensions analysis isn't very complicated, > so it's probably easier to just write it anew. > The existing packages have various features, so someone > can just pick and choose the features they want. > > Shameless plug --- I wrote the ezunits package for Maxima, > which makes extensive use of symbolic computations, > and has a very convenient syntax for annotating units > and for unit conversions, and some interesting random > features; I like this one: > > 1 ` m `` [mile, yard, foot, inch]; > => [6 ` mile, 376 ` yard, 0 ` foot, 608/127 ` inch] > > Maybe ezunits can a source of some inspiration. > I would love that, but I can't read LISP :P > FWIW > > Robert Dodier By the way, do you think is it convenient to create a new wiki page about this topic to summarize all this stuff? I have two questions: first of all, I don't know how to do that, even if it seems pretty easy to modify an existing page. The second question is: on the wiki itself, the developers suggest to create a trac ticket with a wish list, instead of creating wiki pages. Nonetheless, there is that SEP (SAGE Enhancement Proposal) there, which seems a suitable place to write. Last doubt: is anybody going to read it? :) Thanks Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
> > It seemed there was a fair amount of interest, but it there wasn't a > obvious winning solution, and no one had enough incentive to advocate > and push through a full plan. (Usually this isn't an indication that > no one wants it, but that everyone is already busy trying to work on > stuff more relevant to their goals.) I agree > > > I am willing to give new life to this discussion :) I am wondering > > whether a brainstorming system (like the one adopted by Ubuntu - > >http://brainstorm.ubuntu.com/) could be useful to catch the > > community's needs :) > > Yes, and thanks for the effort there. If I remember right, quantities > (?) looked pretty good, but it only can accept numpy scalars. It > would be good to summarize this discussion/the options on a wiki-- > threads are good for a discussion but it becomes hard to get a big > picture once they get so big. > > - Robert You remember right, in fact that was an annoying issue: in my opinion adapting the external package to use the built-in SAGE numerical types is a huge advantage in terms of usability. For this reason, we contacted the quantity author, which took part to the discussion. He recognized that interaction with SAGE types was the first issue to deal with, but at the same time he was a little busy, so he probably thought that we should have figured out the way to solve this first issue at least. I can probably work at a wiki page summarizing this stuff (not that much of material, actually), but do you think anybody is going to take advantage of this? I often see abandoned page in the wiki, and moreover, if there had been enough interest in that, don't you think that people would have shown up in the thread? This group has the advantage that it has still quite good visibility, in my opinion higher than that of the wiki (but I could be wrong). What do you think? If you consider that a good point to start with, you could start creating the wiki page and I could try to edit that a little, and then we will see how it goes. All the other people involved, and interested in a unit package, please show just to say "hi" Regards Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: New symbolic bug?
Hi Stan On Jun 12, 9:42 am, Stan Schymanski wrote: > I had the same question previously, but unfortunately, it passed below > the radars, so I am glad Mauricio's post got picked up. The problem is > that the dict() command automatically converts the variable names to > strings, so the new symbolics can't be used in combination with dict(). > Hope it can be fixed soon, as this breaks quite a few of my notebooks. I agree that I would like to see this fixed (a couple of my notebooks got broken as well :) Anyway, defining the dictionary is fortunately still possible using the syntax Robert suggested, so I'm sticking with this workaround for the time being. Regards Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Dimensional Analysis or Unit Conversion capability?
Hi all On Jun 12, 7:41 am, Robert Bradshaw wrote: > No, but I believe there are several Python packages that do this that > you could install into Sage. (There was talk about adding this at one > point, what is needed is a good list of all the best open-source > packages out there and a discussion of which one to choose and why). > I want to mention that I started a discussion about this same topic a couple of months ago: http://groups.google.com/group/sage-devel/browse_frm/thread/ae18ce618abd66d2/649bd604d0fd20c9?hl=en%CA%89bd604d0fd20c9 as you can see, I already tried to provide a list of all the best open- source packages out there, I also proposed a couple of modifications... I was actually quite interested in that stuff. Nonetheless, there was not enough interest in the community, maybe, so that discussion ended without any concrete effect. I am willing to give new life to this discussion :) I am wondering whether a brainstorming system (like the one adopted by Ubuntu - http://brainstorm.ubuntu.com/ ) could be useful to catch the community's needs :) Regards Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: New symbolic bug?
Good point!
Honestly, I didn't catch I could use a symbolic variable as the left
hand side of the definition of an element in a dictionary, I thought
that should have always been a string
I don't know whether this has to be added in trac, and if so, where (I
imagine this should be related to new symbolic, or coercion or stuff
like that)
Thanks a lot
Regards
Maurizio
> Not sure, if it's not already onhttp://trac.sagemath.org/sage_trac/
> it should be. Probably due to the new symbolics. What you can do is
> make your dictionary cicco = {x: 10}. Making strings work shouldn't
> be too hard, that's what the a.subs(x=10) needs to handle.
>
> - Robert
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[sage-support] New symbolic bug?
This used to work in SAGE 3.x
I'm using SAGE 4.0.1 now
sage: ciccio = {'x':10}
sage: a = 2*x + 5
sage: a
2*x + 5
sage: a.subs(ciccio)
---
TypeError Traceback (most recent call
last)
/home/nslabs/.sage/ in ()
/home/nslabs/Desktop/sage-4.0.1-linux-Ubuntu_9.04-sse2-i686-Linux/
local/lib/python2.5/site-packages/sage/symbolic/expression.so in
sage.symbolic.expression.Expression.substitute (sage/symbolic/
expression.cpp:13696)()
/home/nslabs/Desktop/sage-4.0.1-linux-Ubuntu_9.04-sse2-i686-Linux/
local/lib/python2.5/site-packages/sage/symbolic/expression.so in
sage.symbolic.expression.Expression.coerce_in (sage/symbolic/
expression.cpp:9740)()
/home/nslabs/Desktop/sage-4.0.1-linux-Ubuntu_9.04-sse2-i686-Linux/
local/lib/python2.5/site-packages/sage/structure/parent_old.so in
sage.structure.parent_old.Parent._coerce_ (sage/structure/parent_old.c:
4632)()
/home/nslabs/Desktop/sage-4.0.1-linux-Ubuntu_9.04-sse2-i686-Linux/
local/lib/python2.5/site-packages/sage/structure/parent.so in
sage.structure.parent.Parent.coerce (sage/structure/parent.c:4765)()
TypeError: no canonical coercion from to Symbolic Ring
Is it a known bug?
thanks
Maurizio
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[sage-support] Re: plotting contours using Sage
Although I can't try it right now, I think the main point is this:
> sage: savefig('sage.png')
>
> William
>From SAGE, I think you have always to postpone the savefig() command
after a matplotlib graph generation, to make it save the graph to an
image file. By doing this, the notebook will automatically show the
file just created
Regards
Maurizio
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[sage-support] Re: About Hilbert transform
Interesting... it seems that every transform (Laplace, Fourier,
Hilbert, etc.) are evaluated trying lookup table method first (in
combination with partial decomposition or factorization probably), and
only if this method fails, the integration engine takes place. I'm
wondering whether this solution is the same adopted by mathematica et
al. I know this is certainly the best for speed, which is wonderful!
It seems it's also possible in maple to disable the integration if the
lookup method fails.
According to this, it seems that implementing transforms is just a
matter of providing a vast lookup table, provided that you have a
powerful enough pattern engine, gcd (probably the toughest one),
factorization and other basic stuff... Hopefully (most of) these are
coming with pynac, right?
Regards
Maurizio
On 15 Mag, 17:26, Burcin Erocal wrote:
> Hi Claude,
>
> On Fri, 15 May 2009 06:41:14 -0700 (PDT)
>
> Claude wrote:
>
> > Hi All,
> > Could somebody help me in programming, for example, the Hilbert
> > transform, or Mellin transform, taking Laplace one as a guideline.
> > Thanks in advance.
>
> The documentation of both Hilbert and Mellin transform functions in
> Maple seem to suggest that they use table lookups:
>
> http://www.maplesoft.com/support/help/view.aspx?path=inttrans/hilbert
>
> http://www.maplesoft.com/support/help/view.aspx?path=inttrans/mellin
>
> In the Description section of the pages above, see item 4 in the first
> link and 3 in the second one.
>
> The pattern matching capabilities of the new symbolics will be useful
> here. For some documentation and examples you can try:
>
> sage: var('x,y',ns=1)
> sage: x.subs?
>
> Taking the documentation in the above links as a guideline, such a
> function might:
>
> - transform the given expression to a normal form, using some
> simplification rules
>
> - use the relevant lookup table to do the necessary substitutions
>
> For now, it will be enough to come up with simplification rules that
> apply only to expressions you're interested in. The lookup table can
> also be restricted in this way. Do you have access to a table of
> Hilbert/Mellin transforms relevant for you application?
>
> Can you give examples of expected input and output for the transform
> you want to implement?
>
> Cheers,
> Burcin
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[sage-support] solution_dict trouble?
why is solution_dict not recognized in this case? sage: a 494000*(1.44468576e-24*s + 1.214292456e-15) + 2.4078096e-11 sage: type(a) sage: solve(a,s, solution_dict = True) Traceback (click to the left for traceback) ... TypeError: solve() got an unexpected keyword argument 'solution_dict' Traceback (most recent call last): File "", line 1, in File "/home/notebook/sage_notebook/worksheets/admin/50/code/80.py", line 6, in solve(a,s, solution_dict = True) File "/usr/local/sage/local/lib/python2.5/site-packages/ zope.interface-3.3.0-py2.5-linux-i686.egg/", line 1, in File "/usr/local/sage/local/lib/python2.5/site-packages/sage/ calculus/equations.py", line 1408, in solve return f.solve(*args,**kwds) TypeError: solve() got an unexpected keyword argument 'solution_dict' thanks regards Maurizio --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: programming: define a new function
I think the dirac delta is very widespread both in mechanics and in electronics (because of frequency domain representation of sine function as a tone - dirac(w) - centered at the sine frequency), although I am not sure what about its derivatives. I know this issue has been taken into account in SymPy in a way pretty similar to Mathematica's approach. I frequently use Laplace transform, instead of Fourier (where delta is very common), so I can't tell so much from my experience with the MatLab symbolic package (which used to rely on maple as well, before the MuPad acquisition). Thanks for showing interest, this is very important :) Maurizio > The derivative of the dirac delta shows up in solid mechanics, is that > defined at all? > > I have major problems with Maple because its integration of Heaviside > functions is often wrong. > > Cheers, > > Tim. > > --- > Tim Lahey > PhD Candidate, Systems Design Engineering > University of Waterloohttp://www.linkedin.com/in/timlahey --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] programming: define a new function
Hi all. I'm willing to invest some of my time to understand if I can be able to do a step ahead with symbolic functions. How are special symbolic functions supposed to be defined? I am willing to experiment with delta of dirac function. This has some special properties (see http://en.wikipedia.org/wiki/Dirac_delta_function ), some of them are really useful but I don't know how to define them in a CAS like maxima or SAGE. I'm aware that it is already present in maxima, even though I don't think it is recognized by SAGE. I am wondering whether a viable approach could be to add to calculus.py a section similar to the one of Function_gamma, so that SAGE simply interfaces to maxima. I don't know if this is useful or not. Otherwise, I would be interested in knowing if this could be done with the new symbolic package. Burcin proved to be very helpful in showing me a simple way to define delta function by means of its values and he assigned it as being the derivative of heaviside function (defined in a sort of piecewise function): sage: heaviside(x).diff(x) dirac(x) is there a way to implement the other properties? I am willing to know if is there any documentation about that, because I am not able to find that! I am willing to learn something about pynac, but please feel free to discourage me if you think it is too far away from being ready. Is there any integration or derivation capability ready? Is it possible to start testing it using maxima's integration capabilities? (I don't think so...) I was browsing the todo page ( http://wiki.sagemath.org/symbolics/pynac_todo ) but it seems that many action items went away... are they already accomplished? (what about the TODO showed in http://wiki.sagemath.org/symbolics ?) I have to say I find the actual SAGE documentation seems pretty hard to browse, but could be my fault. Yesterday I lost half an hour looking for a "numerical solve" or something like that, before finding the "find_roots" function. Today, I spent half an hour looking for "differential equation solve" with no success. I am sure I could do some DE solution in the past (something with maxima, something with SymPy, I think, all through SAGE), but I think that I found the way to do it pretty easily browsing the old reference manual... Thanks a lot Maurizio PS: delta of dirac is already in SymPy ( http://code.google.com/p/sympy/issues/detail?id=672&can=1&q=dirac ), am I correct in thinking that the current function definition is different than SAGE? In this case, I assume this could be some good reading, but not necessarily a source of inspiration, right? --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: solve_linear ... how?
Can you open a ticket to add this to the documentation? This certainly
deserves to be there!
On 25 Mar, 17:21, Jason Grout wrote:
> Drini wrote:
>
> > On Mar 25, 9:22 am, kcrisman wrote:
> >> Is it possible that the cvxopt package could help out? Your problem
> >> is not convex optimization per se but maybe it would have something
> >> useful? This package uses LAPACK (also part of Sage), which "provides
> >> routines for solving systems of simultaneous linear equations".
>
> >> Also, is it possible (someone else will have to answer this) that
> >> using the Pynac symbolic variables could help out? But Maxima is
> >> called for solve, so perhaps that wouldn't really help...
>
> >> Or could you just use a big matrix and solve it that way? Maybe I am
> >> misinterpreting your question.
>
> >> I hope *one* of these ideas helps!
>
> >> - kcrisman
>
> > I'm going to check. Actually, what I'm trying to do is find the
> > vertices of a polytope given by some hyperplanes (therefore the linear
> > equations). I know about polymake, but it can't do symbolic
>
> > Like
> > ax+by = 3
> > bx+dy=5
> > a,b,c,d constants
>
> > I know I could get a matrix and use linear algebra to get a fast
> > solution without worrying about symbolics
> > but when the systems are like
> > ax+by=p
> > cx+dy=q
> > with a,b,c,d constants, the vector in Ax=b is not numeric, so I turn
> > to symbolic solving
> > (actually those are simplificatinos, I'm doing 9-variable systems)
>
> > Thatnks for the hints, I will check the options you meantioned
>
> Here it is using linear algebra:
>
> sage: var('a,b,c,d,x,y')
> (a, b, c, d, x, y)
> sage: A=matrix(2,[a,b,c,d]); A
> [a b]
> [c d]
> sage: result=vector([3,5]); result
> (3, 5)
> sage: soln=A.solve_right(result) # you could also do soln=A\result
> sage: soln
> (3/a - b*(5 - 3*c/a)/(a*(d - b*c/a)), (5 - 3*c/a)/(d - b*c/a))
>
> Now, checking our answers:
>
> sage: (a*x+b*y).subs(x=soln[0],y=soln[1]).simplify_full()
> 3
> sage: (c*x+d*y).subs(x=soln[0],y=soln[1]).simplify_full()
> 5
>
> Or just checking it with matrix multiplication:
>
> sage: A*soln
> (a*(3/a - b*(5 - 3*c/a)/(a*(d - b*c/a))) + b*(5 - 3*c/a)/(d - b*c/a),
> c*(3/a - b*(5 - 3*c/a)/(a*(d - b*c/a))) + (5 - 3*c/a)*d/(d - b*c/a))
>
> Let's simplify each entry by applying the "simplify_full" function to
> each entry:
>
> sage: (A*soln).apply_map(lambda x: x.simplify_full())
> (3, 5)
>
> This example probably ought to go into some documentation somewhere...
>
> Jason
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[sage-support] Merge maxima/share stuff into core?
Hi Robert, how are you? I wonder if you do have any new information about you going through all this interesting maxima stuff. I always thought that community stuff have really great features well hidden in it, and I'm really hoping that you are getting some good results. Thank you very much Maurizio On 27 Feb, 17:12, Robert Dodier wrote: > > One of the projects I have on the back burner is to do a review > of the all the junk in maxima/share, to sort out the stuff that > can be merged into the core, or needs clean up, or should be axed. > Feel free to bother me about it if you don't hear anything. > > Robert Dodier --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] SAGE possible improvement
Hello, I'm a happy user of SAGE, and I won't stop thanking all you guys for this wonderful job! Although, I also try to encourage you in getting something better (from my point of view). It seems there has been some serious thinking about including a UNITS of MEASUREMENTS managing package in SAGE: http://groups.google.com/group/sage-devel/browse_frm/thread/8791448b7a303ce9/9dc4cc27e6d4eafb?lnk=gst&q=units#9dc4cc27e6d4eafb >From this, a SAGE trac ticket has been opened (#3852): http://trac.sagemath.org/sage_trac/ticket/3852 This is supposed to be a MAJOR priority ticket, and I think this is a very appropriate description! The ticket has a very good (although a bit old now) description of the different packages available to deal with units in Python. One of the options, was the units package included in Enthought. This had the issue of being under refactoring at that time. The actual situation seems to be that the Enthought package has not been changed (https://svn.enthought.com/enthought/ticket/1524) because of some priority issues in that community (very understandable!), but another interesting package was born from this Enthought discussion: the "quantities" package: http://packages.python.org/quantities/ http://dale.chess.cornell.edu/chess-wiki/Quantities As I can see, this has already been mentioned in a comment to our trac ticket, but with no response. Honestly, I am not able to understand whether this is good enough to be included in SAGE, neither I am able of understanding how much refactoring this would need to make this compatible to all the wonderful symbolic capabilities of SAGE, but nonetheless I think that getting something working at least in the numeric domain, could be very useful With this, I'm not proposing this package over others (for example, Unum looks very mature, but outdated), I'm just asking if one of you can spend some minutes to review our trac ticket about units of measurement (#3852), and to take some other decision about it. Thank you so much Maurizio On 26 Feb, 23:55, Jason Grout wrote: > Maurizio wrote: > > > 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 goodunitsof > > 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... > > I don't know of any progress: > seehttp://trac.sagemath.org/sage_trac/ticket/3852 > > However, I'd love to have the functionality if someone did it! :) > > Jason --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Getting a numerical value
I'd like to jump in the conversation, to describe my own experience. I don't know what about real numbers, but I found out that in that same situation you were talking about (symbolic expression where all the symbols are substituted by numbers eventually), and the expected result is a complex number, using the ComplexField() makes the substitution many orders of magnitude faster than doing .n() Example: CF = ComplexField() evaluated_number = CF(numerical_expression) In this way, I get the result in the fastest way (I'm not that much experienced, though). Any suggestion is appreciated Maurizio On 13 Mar, 15:59, Johan Oudinet wrote: > On Fri, Mar 13, 2009 at 3:19 PM, hpon wrote: > > > Hi, > > > How do I get a numerical value? > > > I have a multi-parameter function where all the parameters have been > > substituted by numerical values. I want Sage to calculate the > > expression's numerical value. At the moment Sage prints: > > > 1/sqrt((sqrt(3)/2 - 0.0173205080757)^2 - 0.0001) - "and so on" > > Do you know how to use the documentation? > For example, in the notebook, I write : a = sqrt(3) > Then, a. gives me the list of methods available... and you can > find numerical_approx which sounds to be what you want... > and if you want details of a specific method, just add a question mark > at the end. For example: > a.numerical_approx? > *** > Type: > Definition: a.numerical_approx(prec, digits) > Docstring: > > Return a numerical approximation of self as either a real or > complex number with at least the requested number of bits or > digits of precision. > > NOTE: You can use foo.n() as a shortcut for > foo.numerical_approx(). > > INPUT: > prec -- an integer: the number of bits of precision > digits -- an integer: digits of precision > > OUTPUT: > A RealNumber or ComplexNumber approximation of self with > prec bits of precision. > > EXAMPLES: > sage: cos(3).numerical_approx() > -0.989992496600445 > > Use the n() shortcut: > sage: cos(3).n() > -0.989992496600445 > > Higher precision: > sage: cos(3).numerical_approx(200) > -0.98999249660044545727157279473126130239367909661558832881409 > sage: numerical_approx(cos(3), digits=10) > -0.9899924966 > sage: (i + 1).numerical_approx(32) > 1. + 1.*I > sage: (pi + e + sqrt(2)).numerical_approx(100) > 7.2740880444219335226246195788 > > *** > > After reading the details, you know you can also use the n() shortcut ;) > > Hope you will find the answer to your next question by yourself ;) > > Best, > > -- > Johan --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Admin Password and Command Line
The way I did it (if I can recall) was: login as sage (or manage?), do "sudo su", do "passwd", set the new password. Something like that should work Maurizio On 13 Mar, 22:32, kaufma wrote: > I am trying to deploy sage on 50 OSX 10.5 lab machines. Is there a way > to set the Administrator password via command line? > > Thanks, > > Eric Kaufmann > Saint Louis University --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Small problem with limit()
This is very interesting...
Is there any wiki or documentation page on the net where it has been
published all the powerful alternatives to maxima we can adopt in
SAGE? I'm sure limit is just one of those which I wasn't aware of!
Maurizio
On Mar 13, 12:34 am, William Stein wrote:
> On Thu, Mar 12, 2009 at 2:19 PM, Ondrej Certik wrote:
>
> > On Thu, Mar 12, 2009 at 1:36 PM, Jose Guzman wrote:
>
> >> Dear colleagues,
>
> >> I've just discovered this wonderful thing called Sage (I am a completely
> >> newbie, my apologizes in advance...), and I have to admit that I am
> >> impressed with Sage!!!. I started yesterday, and came along the tutorial
> >> already. I still miss some more documentation...specially related with
> >> worksheet use/configuration (I did not find any other way to combine
> >> LaTeX, html and sage to create nice worksheets like the ones I saw
> >> today. I simply start a cell with %htmlo %latex or %sage).
>
> >> Anyway, I was playing around with the limits, and after checking the
> >> short tutorial
> >> (http://sage.math.washington.edu/home/elliottd/calctut/limits.html) I
> >> wanted to try something by myself. I found the following inconvenience.
>
> >> sage: g=9.81
> >> sage: t=var('t')
> >> sage: limit(2*g*(t^2-1)/(t-1),t=1)
> >> >>> gives me 39
>
> >> However, if I simplify the equation and calculate the limit...
> >> sage: limit(2*g*(t+1),t=1)
> >> >> gives me the good value 39.276
>
> > I think the good value should actually be:
>
> > In [4]: limit(2*g*(t**2-1)/(t-1), t, 1)
> > Out[4]: 39.24
>
> And here is how one can get the above entirely in Sage using a modern
> symbolic manipulation library called sympy that's included in Sage :-)
>
> teragon:sage-3.4.alpha0 wstein$ sage
> --
> | Sage Version 3.4, Release Date: 2009-03-11 |
> | Type notebook() for the GUI, and license() for information.|
> --
> sage: g=9.81
> sage: import sympy
> sage: t = sympy.var('t')
> sage: sympy.limit(2*g*(t^2-1)/(t-1),t,1)
> 39.24000
>
> William
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[sage-support] Re: VMware Player. Read files from windows OS
What I usually do, to move files in and out from the virtual machine within Windows (maybe it is a little suboptimal way) is to use WinSCP (a freeware software easily found on the internet), which allows me to browse the virtual machine with a "Commander"-like interface, so I can easily move files in and out My 2 cents Maurizio On Mar 12, 10:17 am, hpon wrote: > I can't get it to work. Could you be a bit more specific with the > details (I really have no clue). > > The idea is that I upload the file to VMware Player and then load the > file in Sage, right??? Should I do the Data->Upload before I start > Sage? What would the exact syntax be if the Sage-file is in a folder > on the desktop, for instance? > > I greatly appreciate your help! > > /hpon > > On 11 Mar, 14:22, William Stein wrote: > > > On Wed, Mar 11, 2009 at 4:03 AM, hpon wrote: > > > > Hi, > > > > I'm running Sage from VMware Player (Sage command line) and I would > > > like to load a sage-file that I wrote in Windows XP. Is that > > > possible? How is it done? > > > Data --> Upload or create file ... > > > If your file is called a.sage, then you can load it into your > > worksheet session by typing > > >load a.sage > > > You can edit the uploaded version of the file by selecting > > > Data --> a.sage > > > William --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: sage simplification
What is the reason to have such a bugged function?
When can we trust it?
On 9 Mar, 14:18, Stan Schymanski wrote:
> Just a word of caution with respect to simplify_full().
>
> If your function involves floating point numbers, simplify_full() can
> give an erroneous result (see bug #2604950 in Maxima
> orhttp://groups.google.com/group/sage-devel/browse_thread/thread/561309...).
>
> Also the following example shows a wrong result returned by
> simplify_full() even without floats.
>
> --
> | Sage Version 3.3, Release Date: 2009-02-21 |
> | Type notebook() for the GUI, and license() for information. |
> --
> sage: var('omgo zr ys cz')
> (omgo, zr, ys, cz)
> sage: omgo = (sqrt(-zr^2 + 2*ys*zr + (2*cz - zr)^2 - 2*ys*(2*cz - zr))
> + 2*zr- 2*cz)/(2*zr - 2*cz)
> sage: omgo.simplify_full()
> (I*sqrt(cz - ys)*sqrt(zr - cz) + zr - cz)/(zr - cz)
>
> Now plucking in a few numbers for the variables shows that the results
> before and after simplification are very different.
>
> sage: omgo(cz=10,ys=5,zr=4).n()
> 0.0871290708247230
> sage: omgo.simplify_full()(cz=10,ys=5,zr=4).n()
> 1.91287092917528
>
> This is taken from the following
> thread:http://groups.google.com/group/sage-support/browse_thread/thread/5d8e...
>
> My personal conclusion is to stay away from simplify_full() until I
> know when to expect correct results from it.
>
> Stan
>
> On Jan 20, 10:56 am, Jason Grout wrote:
>
> > Tim Lahey wrote:
> > > However, in my version of Sage (3.2), the functions simplify_full()
> > > and simplify_trig() only seem to be defined on objects not as
> > > general functions. Unless I'm missing something.
>
> > I noticed that too. Does anyone object to making at least simplify_full
> > a top-level function?
>
> > Jason
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[sage-support] Re: Inverse laplace transform and Post integration formula - symbolic derivative?
Well, I'm already starting to bother!! :) If you need any help in reviewing that stuff (provided that I'm not a mathematician), let me know. Apart from the fact that I'll be out of country for work during next week.. See you in 7 days!! Maurizio On 27 Feb, 17:12, Robert Dodier wrote: > On Feb 26, 4:24 pm, mabshoff > dortmund.de> wrote: > > Have you check with the Maxima folks? There is quite a bit of code in > > contrib that isn't particularly well integrated. IMHO this is a place > > where the Maxima folks could improve Maxima a lot by integrating the > > code into the main Maxima codebase, i.e. there is a solver in there > > that can handle a lot more systems than the default one and most > > people will not look for another solver once the one in default Maxima > > does not do what they want it to do. > > One of the projects I have on the back burner is to do a review > of the all the junk in maxima/share, to sort out the stuff that > can be merged into the core, or needs clean up, or should be axed. > Feel free to bother me about it if you don't hear anything. > > Robert Dodier --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
[sage-support] Re: Inverse laplace transform and Post integration formula - symbolic derivative?
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 wrote: > On Thu, Feb 26, 2009 at 5:32 PM, Maurizio 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/2006/36.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 > > 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 suppor
[sage-support] Re: Inverse laplace transform and Post integration formula - symbolic derivative?
Robert, do you consider these issues relevant? If so, do you consider worthwhile to forward this discussion to the devel group? I'm sorry, but I'm always reluctant about choosing where to post my (too numerous) questions. Regards Maurizio On 26 Feb, 23:32, Maurizio 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.htmlhttp://www.math.utexas.edu/pipermail/maxima/2006/36.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. > > 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 > 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 > > > 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 -~--~~~~--~~--~--~---
[sage-support] Re: Inverse laplace transform and Post integration formula - symbolic derivative?
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/2006/36.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. 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/7f33e7001e480d47/4f46fff6a387becc?lnk=gst&q=maxima+delta#4f46fff6a387becc 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/8791448b7a303ce9/9dc4cc27e6d4eafb?lnk=gst&q=units#9dc4cc27e6d4eafb Please, forgive me again for being so annoying Maurizio On 26 Feb, 23:16, Robert Bradshaw 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 > > 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 -~--~~~~--~~--~--~---
[sage-support] Re: Inverse laplace transform and Post integration formula - symbolic derivative?
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 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 -~--~~~~--~~--~--~---
[sage-support] Inverse laplace transform and Post integration formula - symbolic derivative?
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. 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? Thank you very much Regards Maurizio Reference: http://www.rose-hulman.edu/~bryan/invlap.pdf --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
