Re: [sage-support] Re: Bessel Function Zeroes
On 07/ 4/10 07:25 AM, Jason Grout wrote: You could also use mpmath to calculate the roots: http://mpmath.googlecode.com/svn/tags/0.15/doc/build/functions/bessel.html?highlight=bessel (specifically, see the example "Roots of Bessel functions are often used:") Jason It would be good if how to find these was more obvious. Roots of Bessel functions are pretty common to want to find (at least in fields of engineering I've worked in). It's not obvious that one would use the Sage interface to mpmath to compute these. MMA has these as BesselJZero[] and BesselYZero[] http://reference.wolfram.com/mathematica/ref/BesselJZero.html http://reference.wolfram.com/mathematica/ref/BesselYZero.html If nobody beats me to it, when the OpenSolaris and 64-bit SPARC ports are finished and I can concentrate on other aspects of Sage, I'll look into making these more easily available. Dave -- 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] numerical evaluation of symbolic expressions
Why is evaluating this expression problematical?
y1(x)=x^2;y2(x)=5-x;
a0=1;an=3;Delta=(an-a0)/n;p(k)=a0+(k-1/2)*Delta;
I(n)=sum(abs(y2(p(k))-y1(p(k)))*Delta,k,1,n);
N(I(10))
SAGE respons:
Traceback (most recent call last):
File "", line 1, in
File "_sage_input_109.py", line 9, in
open("___code___.py","w").write("# -*- coding: utf-8 -*-\n" +
_support_.preparse_worksheet_cell(base64.b64decode("eTEoeCk9eF4yO3kyKHgpPTUteDsKYTA9MTthbj0zO0RlbHRhPShhbi1hMCkvbjtwKGspPWEwKyhrLTEvMikqRGVsdGE7Ckkobik9c3VtKGFicyh5MihwKGspKS15MShwKGspKSkqRGVsdGEsaywxLG4pOwpOKEkoMTApKQ=="),globals())
+"\n"); execfile(os.path.abspath("___code___.py"))
File "", line 1, in
File "/tmp/tmpk0DnhJ/___code___.py", line 6, in
N(I(_sage_const_10 ))
File "", line 1, in
File "/home/sage/sage/local/lib/python2.6/site-packages/sage/misc/
functional.py", line 1165, in numerical_approx
return x.numerical_approx(prec)
File "expression.pyx", line 3797, in
sage.symbolic.expression.Expression.n (sage/symbolic/expression.cpp:
17022)
TypeError: cannot evaluate symbolic expression numerically
If I leave out the N( )-operator on the last line the block evaluates
to
1/500*sum(abs(-4*k^2 - 56*k + 329), k, 1, 10)
which can be evaluated in a new inputbox. Why not in one step?
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Re: [sage-support] numerical evaluation of symbolic expressions
Hi, On Sun, 4 Jul 2010 05:36:50 -0700 (PDT) dirkd wrote: > Why is evaluating this expression problematical? > > y1(x)=x^2;y2(x)=5-x; > a0=1;an=3;Delta=(an-a0)/n;p(k)=a0+(k-1/2)*Delta; > I(n)=sum(abs(y2(p(k))-y1(p(k)))*Delta,k,1,n); > N(I(10)) > > SAGE respons: > File "expression.pyx", line 3797, in > sage.symbolic.expression.Expression.n (sage/symbolic/expression.cpp: > 17022) > TypeError: cannot evaluate symbolic expression numerically > > > If I leave out the N( )-operator on the last line the block evaluates > to > > > 1/500*sum(abs(-4*k^2 - 56*k + 329), k, 1, 10) > > which can be evaluated in a new inputbox. Why not in one step? The result returned from maxima uses a symbolic function object created on the fly. This is quite different from the sum() function available on the command line, and unfortunately, it doesn't define a numerical evaluation function, _evalf_(). If no one beats me to it, I will provide a symbolic sum function in the next few days. I opened a ticket for this problem: http://trac.sagemath.org/sage_trac/ticket/9424 Thanks for the report. Burcin -- 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] Why does LatticePolytope not implement a special __eq__ function?
Hi list, im just playing around with sage and LatticePolytopes and im wondering why theres no __eq__ implementet for them. if i have this code: s1 = LatteciPolytope(matrix([[1,0,-1],[0,1,-1]]) s2 = LatteciPolytope(matrix([[1,0,-1],[0,1,-1]]) then s1 == s2 evals to false. thats right in the sentence of ref-equality but in my eyes two polytopes are equal, if they live in the same space (in this case, on the same Lattice) and have the same edges. Is there any reason, why its not implemented that way? greatz Johannes -- 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] Subclass from LatticePolytope
Hi list, i just tried to create a extended Version of LatticePolytope, but it did not work. I always get the following error: Error when calling the metaclass bases function() argument 1 must be code, not str. i found out this is because LatticePolytope is not a class, but a function. otherwise, the type of LatticePolytope(somePoints) is given as: sage.geometry.lattice_polytope.LatticePolytopeClass. How can i extend this? Where can i find informations about this class? greatz Johannes -- 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] Some R integration samples - is there better way to do it?
Hi, recently I have given short introductory talk about Sage and questions about integration with R arisen. Results of quickly put together code is now at http://sagenb.org/home/pub/2232/ - especially, the question was: "I have variable named x in R environment and want to get its value, or variable named x inside Sage environment and push its value into R, but keep the name." - what I was able to think about is quick hack with .GlobalEnv of R, but is there better way to do what is presented in the notebook linked above? Is there some syntax like r["x"]=[1,2,3] or sth? If there is, I haven't noticed it yet - would be thankful for hints. Cheers, Andrzej. -- 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
Re: [sage-support] Some R integration samples - is there better way to do it?
Hi Andrezj,
On Sun, Jul 4, 2010 at 11:54 PM, Andrzej Giniewicz wrote:
> Hi,
>
> recently I have given short introductory talk about Sage and questions
> about integration with R arisen. Results of quickly put together code
> is now at http://sagenb.org/home/pub/2232/ - especially, the question
> was: "I have variable named x in R environment and want to get its
> value, or variable named x inside Sage environment and push its value
> into R, but keep the name." - what I was able to think about is quick
> hack with .GlobalEnv of R, but is there better way to do what is
> presented in the notebook linked above? Is there some syntax like
> r["x"]=[1,2,3] or sth? If there is, I haven't noticed it yet - would
> be thankful for hints.
>
> Cheers,
> Andrzej.
>
> --
> 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
>
This should do what you wanted:
sage: r('x <- c(1,2,3)')
[1] 1 2 3
sage: r('x')
[1] 1 2 3
sage: sageobj(r('x')) # r('x').sage() works too
[1, 2, 3]
sage: r([1, 2, 3])
[1] 1 2 3
---
Tim Joseph Dumol
http://timdumol.com
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Re: [sage-support] Some R integration samples - is there better way to do it?
On Mon, Jul 5, 2010 at 12:13 AM, Tim Joseph Dumol wrote:
> Hi Andrezj,
>
> On Sun, Jul 4, 2010 at 11:54 PM, Andrzej Giniewicz wrote:
>> Hi,
>>
>> recently I have given short introductory talk about Sage and questions
>> about integration with R arisen. Results of quickly put together code
>> is now at http://sagenb.org/home/pub/2232/ - especially, the question
>> was: "I have variable named x in R environment and want to get its
>> value, or variable named x inside Sage environment and push its value
>> into R, but keep the name." - what I was able to think about is quick
>> hack with .GlobalEnv of R, but is there better way to do what is
>> presented in the notebook linked above? Is there some syntax like
>> r["x"]=[1,2,3] or sth? If there is, I haven't noticed it yet - would
>> be thankful for hints.
>>
>> Cheers,
>> Andrzej.
>>
>> --
>> 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
>>
>
> This should do what you wanted:
>
> sage: r('x <- c(1,2,3)')
> [1] 1 2 3
> sage: r('x')
> [1] 1 2 3
> sage: sageobj(r('x')) # r('x').sage() works too
> [1, 2, 3]
> sage: r([1, 2, 3])
> [1] 1 2 3
Oh, and:
sage: r.set('y', r([1,2,3]))
sage: r('y')
[1] 1 2 3
Try:
sage: r.
for more commands.
> ---
> Tim Joseph Dumol
> http://timdumol.com
>
--
Tim Joseph Dumol
http://timdumol.com
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[sage-support] Re: Which python for sage?
On Jul 3, 8:33 am, William Stein wrote: > Sage can't switch to Python 3 until every single Python package in > Sage is ported to Python 3. > This is far from done. It's possible that for some packages, nobody > is even working on doing a port. In such cases, our only hope is to > either do the port ourselves or remove the package from Sage, which > may both be incredibly difficult. I've heard Twisted may be an > example of such a package, but there might be others. Even numpy > hasn't been ported to Python 3 yet, though at least there work is > rumored to be in progress. Of course, you understand these issues better than I do. I didn't even consider that Sage has so many third-party libraries at the Python level. So yeah, I can see that it could take a long time to do such a conversion. Even so, I would suggest a more developed policy than just that you can't do it right now. Certainly at first glance, Python 3 looks a really good idea. Maybe at second glance, the conversion cost is very high for many projects and you could estimate that it will take many years for the world to switch. (But note that the same was true of a really great editor called NEdit and Unicode, and the result in the long run was that it hurt NEdit a lot.) In any case the all-or-nothing answer cannot be completely true. After all, you have interface support for packages written entirely in C or whatever other language. So how could it be that if you were in Python 3, then Python 2.* would be the one language that you can't support at all? What would you do if you wanted to support a Python 3 package? -- 0 Greg Kuperberg 01234 Professor of Mathematics 02413 University of California, Davis 03142 http://www.math.ucdavis.edu/~greg/ 04321 g...@math.ucdavis.edu -- 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
Re: [sage-support] Subclass from LatticePolytope
Hi, Johannes, On Jul 4, 2010, at 07:24 , Johannes wrote: i just tried to create a extended Version of LatticePolytope, but it did not work. I always get the following error: Error when calling the metaclass bases function() argument 1 must be code, not str. i found out this is because LatticePolytope is not a class, but a function. otherwise, the type of LatticePolytope(somePoints) is given as: sage.geometry.lattice_polytope.LatticePolytopeClass. How can i extend this? Where can i find informations about this class? I can't help with the details of the Lattice Polytope code, but this may help. Since I'm not sure of your understanding of the Sage system, I'm not sure of how much you know, so this is basic info: In general, given a Sage (or Python) object 'x', typing 'x. [TAB]' (i.e., 'x.' followed by the TAB key) will give you a list of methods associated to 'x' (or to its type; also, not all listed items may be implemented for a given object). Also, typing "str[TAB]" will give you a list of all known (global) names beginning with "str". If you type something like "s1.polar?" (from your previous email), Sage will respond with whatever documentation is provided by the implementor of the "polar()" method for Lattice Polytopes. With a double "??", you get documentation and possibly the code that implements it (if Sage can find it). For this to work, "s1" must be the full name of an object, class, function, or method (sometimes 'str[tab]?' works wonders :-}). At the beginning of each of the latter output lists is a line beginning "File: ". This line contains the full path to the source file where the code lives, so you can examine things like class definitions and function or method implementations. HTH Justin -- Justin C. Walker, Curmudgeon at Large Institute for the Absorption of Federal Funds --- My wife 'n kids 'n dogs are gone, I can't get Jesus on the phone, But Ol' Milwaukee's Best is my best friend. --- -- 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
Re: [sage-support] Subclass from LatticePolytope
thnx, i did not know all about the sagehelp. but the ?? is a wonderfull feature. I'll look at the code next, and i hope it helps me somehow. gretz Johannes. Am 04.07.2010 23:52, schrieb Justin C. Walker: > Hi, Johannes, > > On Jul 4, 2010, at 07:24 , Johannes wrote: > >> i just tried to create a extended Version of LatticePolytope, but it did >> not work. >> I always get the following error: >> Error when calling the metaclass bases function() argument 1 must be >> code, not str. >> i found out this is because LatticePolytope is not a class, but a >> function. >> otherwise, the type of LatticePolytope(somePoints) is given as: >> sage.geometry.lattice_polytope.LatticePolytopeClass. >> How can i extend this? >> Where can i find informations about this class? > > I can't help with the details of the Lattice Polytope code, but this > may help. Since I'm not sure of your understanding of the Sage > system, I'm not sure of how much you know, so this is basic info: > > In general, given a Sage (or Python) object 'x', typing 'x.[TAB]' > (i.e., 'x.' followed by the TAB key) will give you a list of methods > associated to 'x' (or to its type; also, not all listed items may be > implemented for a given object). > > Also, typing "str[TAB]" will give you a list of all known (global) > names beginning with "str". > > If you type something like "s1.polar?" (from your previous email), > Sage will respond with whatever documentation is provided by the > implementor of the "polar()" method for Lattice Polytopes. With a > double "??", you get documentation and possibly the code that > implements it (if Sage can find it). For this to work, "s1" must be > the full name of an object, class, function, or method (sometimes > 'str[tab]?' works wonders :-}). > > At the beginning of each of the latter output lists is a line > beginning "File: ". This line contains the full path to the source > file where the code lives, so you can examine things like class > definitions and function or method implementations. > > HTH > > Justin > > -- > Justin C. Walker, Curmudgeon at Large > Institute for the Absorption of Federal Funds > --- > My wife 'n kids 'n dogs are gone, > I can't get Jesus on the phone, > But Ol' Milwaukee's Best is my best friend. > --- > > -- 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] An argument for more direct axiom integration
I discovered the following article online (http://amca01.wordpress.com/ 2010/01/08/symbolic-integration-with-an-open-source-cas/). Suggesting that there are certain cases, in which sage fails to integrate functions that can be integrated. The functions that the author of this article said could not be integrated by sage, in fact, were not integrated when I tested them today with the latest version that I just now installed. In all fairness, Sage is very good and solves most all of the integrals, but axiom can solve some cases where sage cannot. For this reason, I feel it would be nice to have a more directly integrated axiom to solve these problems and integrated what sage cannot do normally. -- 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
Re: [sage-support] An argument for more direct axiom integration
Great idea - you could add an algorithm="axiom" option to sage's integrate command. On Sunday, July 4, 2010, John wrote: > I discovered the following article online (http://amca01.wordpress.com/ > 2010/01/08/symbolic-integration-with-an-open-source-cas/). Suggesting > that there are certain cases, in which sage fails to integrate > functions that can be integrated. The functions that the author of > this article said could not be integrated by sage, in fact, were not > integrated when I tested them today with the latest version that I > just now installed. In all fairness, Sage is very good and solves most > all of the integrals, but axiom can solve some cases where sage > cannot. For this reason, I feel it would be nice to have a more > directly integrated axiom to solve these problems and integrated what > sage cannot do normally. > > -- > 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 > -- William Stein Professor of Mathematics University of Washington http://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 URL: http://www.sagemath.org
