[sage-support] Re: Solving a 2nd order linear ODE with initial conditions

2009-02-01 Thread David Joyner
On Sun, Feb 1, 2009 at 5:34 PM, Christophe Deroulers wrote: > > > When one looks at what Sage sends to Maxima when "desolve(diff(y,x, > 2)+y(x)==0,y,[0,3,2])" is called, it turns out that Maxima receives > something like > > my_ode: diff('y(x),x,2) + 'y(x) = 0; > my_sol: ode2(my_ode, 'y(x), x);

[sage-support] Re: Evaluate a derivative at one point

2009-02-01 Thread Mike Hansen
Hi Christophe, On Sun, Feb 1, 2009 at 3:08 PM, Christophe Deroulers wrote: > > Hello, > > Is there a way in Sage to express the derivative at one point of a > "formal" function? There's currently no way to do this right now. I have a bit of code I started at Sage Days 13 to allow one to do th

[sage-support] Evaluate a derivative at one point

2009-02-01 Thread Christophe Deroulers
Hello, Is there a way in Sage to express the derivative at one point of a "formal" function? I mean: something equivalent to "at(diff(f(x),x), x=123);" in Maxima or "eval(diff(f(x),x), x=123);" or "D(f)(123);" in Maple or "D[f [x],x]/.x->123" or "Derivative[1][f][123]" in Mathematica. For ins

[sage-support] Re: Solving a 2nd order linear ODE with initial conditions

2009-02-01 Thread Christophe Deroulers
On Jan 21, 3:05 am, David Joyner wrote: > (However, for other problems, this trick will not work so well.) > I know about the problem with desolve and don't know how > to "fix" it (though, it is actually documented that way, as you will see if > you type desolve?). Sorry. I guess you know all t

[sage-support] Re: read very large integer matrix from file

2009-02-01 Thread John Matrix
Thanks, Fabio, that seems to solve my problem indeed! --~--~-~--~~~---~--~~ 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 grou

[sage-support] Re: read very large integer matrix from file

2009-02-01 Thread Fabio Tonti
What about http://groups.google.com/group/sage-devel/browse_thread/thread/90ae1dcee213a9c7?pli=1? Fabio On Sun, Feb 1, 2009 at 8:20 AM, John Matrix wrote: > > > Hi David and Minh, > > Thanks for your comments! > @David > In the worst case, the matrix will have roughly 17000 rows and > columns.

[sage-support] Re: read very large integer matrix from file

2009-02-01 Thread John Matrix
Hi David and Minh, Thanks for your comments! @David In the worst case, the matrix will have roughly 17000 rows and columns. I could reduce it with some effort, but I'll first try to figure out if it's worth it. I don't know Python very well, but I could probably learn that much. Alternatively, I

[sage-support] Re: read very large integer matrix from file

2009-02-01 Thread Minh Nguyen
Hi John, On Sun, Feb 1, 2009 at 3:18 PM, John Matrix wrote: [...] > I'd like to read a very large integer dense square matrix into sage > from a file, in order to determine its rank. I could not find much > information on what format I should store the matrix in, and what > commands to use to re

[sage-support] Re: read very large integer matrix from file

2009-02-01 Thread David Joyner
I guess it depends on what "very large" means. Do you know any Python? If so, one option is just read in the file of entries then write a python/sage script to create the matrix in Sage from that. I think large integer matrices use linbox, which I think is easily capable of some matrix computation

[sage-support] read very large integer matrix from file

2009-02-01 Thread John Matrix
Hi, I'd like to read a very large integer dense square matrix into sage from a file, in order to determine its rank. I could not find much information on what format I should store the matrix in, and what commands to use to read it. Any help would be appreciated. Thanks! --~--~-~--~