Re: [sage-support] Re: [ANN] New free tool for TSP solving
Hell !! I have updated OO TSP page with link to the OpenOpt TSP class file: Thank you ! It looks like you use the MTZ formulation, with some additional simplifications when there are vertices of in/out degree 1 in the graph :-) The formulation we have in Sage should be very competitive, as it is more topological than MZT.. But of course it probably depends on the instances you want to solve, too :-) Have fnnn !! Nathann -- You received this message because you are subscribed to the Google Groups sage-support group. 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. Visit this group at http://groups.google.com/group/sage-support?hl=en.
Re: [sage-support] Re: Sage's running too slowly
On 3 September 2012 04:49, Nathann Cohen nathann.co...@gmail.com wrote: Honestly I don't think it's very constructive to tell users that they should install a different operating system in order to use Sage, and that is basically what this dual-booting suggestion amounts to I totally agree with that. And I think that it is not very constructive to say that Sage supports windows either, when it requires users to install a virtual machine. It does not, and saying the opposite is bad avertisement. I've had a few disagreements with Nathann before, but in this case I agree with him. It's probably true that 99% of Windows software would work on Linux if you run it under a virtual machine, but it's not true to say it supports Linux. I run 3 versions of Windows on my OpenSolaris machine (Windows XP 64-bit, Windows XP and Windows 7). Does it really mean all the software I run supports OpenSolaris? I would say NO. As a matter of interest, does this sub-domain need to exist http://windows.sagemath.org/ Dave -- You received this message because you are subscribed to the Google Groups sage-support group. 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. Visit this group at http://groups.google.com/group/sage-support?hl=en.
[sage-support] how to factorize an expression with constant variables ?
Hello,
I would like to factorize an expression with sage that contains constant
variables (i.e. parameters), but I cannot figure out how to do that.
Here is an example : x, y are variables and A is a parameter
*
var('A x y')
f = A*x + x + A^2*exp(y) + y
print (f.factor())
*
Sage returns 'A^2*e^y + A*x + x + y'.
Instead, I would like that sage returns '(A+1)*x + (A^2+1)*exp(y)'.
How to do that ?
Thank you
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[sage-support] Re: Sage's running too slowly
On Monday, September 3, 2012 4:49:05 AM UTC+1, Nathann Cohen wrote: It supports Windows as much as any Linux software that does not support windows -- install a virtual machine and run it inside. And it convices people that Sage is hard to install, hard to use, and slower than it actually is :-P Given the lack of fork() on windows, running Sage in a virtual machine is probably faster than running it under Cygwin. Especially if you have a modern CPU with hardware virtualization support. Also, Cygwin is 32-bit only. -- You received this message because you are subscribed to the Google Groups sage-support group. 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. Visit this group at http://groups.google.com/group/sage-support?hl=en.
Re: [sage-support] Re: Sage's running too slowly
On 3 September 2012 08:49, Volker Braun vbraun.n...@gmail.com wrote: On Monday, September 3, 2012 4:49:05 AM UTC+1, Nathann Cohen wrote: It supports Windows as much as any Linux software that does not support windows -- install a virtual machine and run it inside. And it convices people that Sage is hard to install, hard to use, and slower than it actually is :-P Given the lack of fork() on windows, running Sage in a virtual machine is probably faster than running it under Cygwin. Especially if you have a modern CPU with hardware virtualization support. Also, Cygwin is 32-bit only. I don't doubt what you say about speed on Cygwin or the fact Cygwin is only 32-bit. But Nathann still makes valid points. I produce software which runs on Unix and Linux, but I never claim it works on Windows, despite the fact I'm 99.999% sure it would compile on a virtual machine running Linux, Solaris, OpenBSD, FreeBSD, SCO or any Unix or Unix-like system. Dave -- You received this message because you are subscribed to the Google Groups sage-support group. 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. Visit this group at http://groups.google.com/group/sage-support?hl=en.
Re: [sage-support] Re: plot color computet by function
Am Freitag, 31. August 2012 12:08:32 UTC+2 schrieb David Joyner: On Fri, Aug 31, 2012 at 4:53 AM, danjo86 dan...@sommerfeld-timmaspe.dejavascript: wrote: Right! It's a remain of tryings... Does this section help? http://www.sagemath.org/doc/reference/sage/plot/colors.html -- You received this message because you are subscribed to the Google Groups sage-support group. To post to this group, send email to sage-s...@googlegroups.comjavascript:. To unsubscribe from this group, send email to sage-support...@googlegroups.com javascript:. Visit this group at http://groups.google.com/group/sage-support?hl=en. Hallo, now i am sure, that i am in the position to specify my problem: As you has seen, i have the global variables x,y. But I need that the plotfunction uses his own local variables. So that the point (-2,1) get the color mandel(-2,1). Maybe now anyone can help me. Thanks -- You received this message because you are subscribed to the Google Groups sage-support group. 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. Visit this group at http://groups.google.com/group/sage-support?hl=en.
[sage-support] Re: plot color computet by function
On 9/3/12 4:43 AM, danjo86 wrote: Am Freitag, 31. August 2012 12:08:32 UTC+2 schrieb David Joyner: On Fri, Aug 31, 2012 at 4:53 AM, danjo86 dan...@sommerfeld-timmaspe.de javascript: wrote: Right! It's a remain of tryings... Does this section help? http://www.sagemath.org/doc/reference/sage/plot/colors.html http://www.sagemath.org/doc/reference/sage/plot/colors.html -- You received this message because you are subscribed to the Google Groups sage-support group. To post to this group, send email to sage-s...@googlegroups.com javascript:. To unsubscribe from this group, send email to sage-support...@googlegroups.com javascript:. Visit this group at http://groups.google.com/group/sage-support?hl=en http://groups.google.com/group/sage-support?hl=en. Hallo, now i am sure, that i am in the position to specify my problem: As you has seen, i have the global variables x,y. But I need that the plotfunction uses his own local variables. So that the point (-2,1) get the color mandel(-2,1). Maybe now anyone can help me. I think the problem is that the rgbcolor function is not evaluated for every point. It's evaluated once for the entire plot. Instead, I think using the 2d matrix_plot [1] or density_plot [2] would give you the colors you want. Or you can use complex_plot [3] There may also be some interesting demos here for you: http://wiki.sagemath.org/interact/fractal Thanks, Jason [1] http://www.sagemath.org/doc/reference/sage/plot/matrix_plot.html#sage.plot.matrix_plot.matrix_plot [2] http://www.sagemath.org/doc/reference/sage/plot/density_plot.html#sage.plot.density_plot.density_plot [3] http://www.sagemath.org/doc/reference/sage/plot/complex_plot.html#sage.plot.complex_plot.complex_plot -- You received this message because you are subscribed to the Google Groups sage-support group. 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. Visit this group at http://groups.google.com/group/sage-support?hl=en.
Re: [sage-support] how to factorize an expression with constant variables ?
On 09/03/12 03:26, mazkime wrote:
Hello,
I would like to factorize an expression with sage that contains constant
variables (i.e. parameters), but I cannot figure out how to do that.
Here is an example : x, y are variables and A is a parameter
*
var('A x y')
f = A*x + x + A^2*exp(y) + y
print (f.factor())
*
Sage returns 'A^2*e^y + A*x + x + y'.
Instead, I would like that sage returns '(A+1)*x + (A^2+1)*exp(y)'.
Did you mean,
f = A*x + x + A^2*exp(y) + exp(y)
in the input? Your desired output is not equal to f. If you did, this
can sort of be done:
sage: A,x,y = var('A,x,y')
sage: f = A*x + x + A^2*exp(y) + exp(y)
sage: result = 0
sage: basis = [x, exp(y)]
sage: for b in basis:
: coeff = f.collect(b).coefficient(b)
: f -= coeff*b
: result += coeff*b
:
sage: result
(A + 1)*x + (A^2 + 1)*e^y
But it relies on collect() doing the right thing, which won't always
happen unfortunately. You may need to call expand() right before
collect() on some expressions. Others just won't work at all.
I suggest sprinkling simplify() in there, and checking that bool(f==0)
at the end so you can at least tell when it has failed (or succeeded
unprovably).
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Re: [sage-support] how to factorize an expression with constant variables ?
On 09/03/12 14:49, mazkime wrote:
Thank you for your answer and sorry for the typo mistake.
Your solution works well with the example given but doesn't work as I
would like with exponents (x^2, ...).
Yeah it's not ideal. I needed to do this with symbolic derivatives, and
the method I posted doesn't work for those either. My workaround was to
replace e.g. f'(-1) with var('d1fx0') before trying the collect() trick.
The same thing might work here -- replacing x^2 by var('x2') or
something -- but it does get ugly after a while.
What I would like to get is Sage returning expressions with coefficients
sorted by the value of the exponents, like when using multivariate
polynomial rings.
...
Is there a solution to my problem ?
If there is, I'd like to know it!
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[sage-support] Re: plot color computet by function
First of all, thanks for help. You got exactly the point. I saw the example you post. But is there a possibility, that i calculate mandel within the plotfunction? -- You received this message because you are subscribed to the Google Groups sage-support group. 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. Visit this group at http://groups.google.com/group/sage-support?hl=en.
[sage-support] Dual of an ideal
Hi, How can I calculate the dual of an ideal using sage? Thanks. Cindy -- You received this message because you are subscribed to the Google Groups sage-support group. 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. Visit this group at http://groups.google.com/group/sage-support?hl=en.
