[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-07 Thread David Joyner
On Wed, Oct 7, 2009 at 9:45 AM, ma...@mendelu.cz ma...@mendelu.cz wrote: ... Still do not understand the problem related to desolve_laplace Should only the way how to define variables been fixed? Or should be fixed the fact, that the equation is expected as lambda expression? The

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-06 Thread ma...@mendelu.cz
On 5 říj, 23:14, calcp...@aol.com wrote: Wow, this sounds like a big bug.  I will be using Sage quite a bit in a Calculus I and II lab in the Spring.  Is this going to be huge problem? Do not think that this will be huge problem. You cal allwayas use Maxima instead Sage. In notebook you can

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-06 Thread ma...@mendelu.cz
New version (slightly cleaner and more readable the previous one and better in the sense that desolve with initial condition returns the right-hand side only) is at http://user.mendelu.cz/marik/temp/desolvers.py However - we still call ode2 two times when solving second order ode with initial

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-06 Thread kcrisman
On Oct 6, 5:53 am, ma...@mendelu.cz ma...@mendelu.cz wrote: New version (slightly cleaner and more readable the previous one and better in the sense that desolve with initial condition returns the right-hand side only) is athttp://user.mendelu.cz/marik/temp/desolvers.py However - we still

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-06 Thread ma...@mendelu.cz
On 6 říj, 15:21, kcrisman kcris...@gmail.com wrote: ere. Thanks for taking the time to look into this! Thank you for your help. I posted the patch http://trac.sagemath.org/sage_trac/ticket/6479 which (I hope) fixes ic2 and bc2 commands. Results of tests have been updated and test related to

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-05 Thread ma...@mendelu.cz
On 4 říj, 14:57, Marshall Hampton hampto...@gmail.com wrote: For the first time dealing with some of these things the IRC channel sage-devel is very helpful. It would be great if you could do this. I am happy to review it, you can put me as a CC: or reviewer. I think your solution sounds

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-05 Thread kcrisman
On Oct 5, 3:08 am, ma...@mendelu.cz ma...@mendelu.cz wrote: On 4 říj, 14:57, Marshall Hampton hampto...@gmail.com wrote: For the first time dealing with some of these things the IRC channel sage-devel is very helpful.  It would be great if you could do this. I am happy to review it, you

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-05 Thread ma...@mendelu.cz
I have one solution :) very very poor (really very poor) solution and from this reason I will not supply the patch yet. The method is to call ode2 again, now together with ic2 in one new call of Maxima. The (fixed) file is desolvers.py is at http://user.mendelu.cz/marik/temp/desolvers.py

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-05 Thread calcpage
Wow, this sounds like a big bug. I will be using Sage quite a bit in a Calculus I and II lab in the Spring. Is this going to be huge problem? HTH, A. Jorge Garcia http://calcpage.tripod.com Teacher Professor Applied Mathematics, Physics  Computer Science Baldwin Senior High School Nassau

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-04 Thread ma...@mendelu.cz
about Python or Mercurial either.  If you don't have a Trac account, email William privately for one, and then you can log this as a ticket and create a patch.  In the meantime the documentation for doing very basic patches is pretty good in the developer's guide, which I think is linked on

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-04 Thread Marshall Hampton
For the first time dealing with some of these things the IRC channel sage-devel is very helpful. It would be great if you could do this. I am happy to review it, you can put me as a CC: or reviewer. I think your solution sounds good. -Marshall Hampton On Oct 4, 1:48 am, ma...@mendelu.cz

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-03 Thread David Joyner
This is a known bug. Marshall and I tried to fix it during a SageDays in Seattle but failed to figure out the magic in Robert Bradshaw's code for desolve. I think it is easy to fix for those who know how to fix it easily, but that rules me out:-) On Sat, Oct 3, 2009 at 3:30 AM,

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-03 Thread Marshall Hampton
Yes, the parsing of output from maxima is currently pretty messed up. I think its fair to say that symbolic ODEs are a real weak point in Sage right now. I'm not sure when I will have enough time to devote to really fixing this; my main interest is in using them to teach and I am not an expert

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-03 Thread ma...@mendelu.cz
it seems that sage passes to Maxima something like ic2('y(x)= %k1*sin(2*x)+%k2*cos(2*x),x = 0,'y(x) = 0, D[0]y(0) = 0) and it seems that maxima expects something like ic2(y= %k1*sin(2*x)+%k2*cos(2*x),x = 0,y = 0, anything = 0) Does this help? Robert On 3 říj, 16:22, Marshall Hampton

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-03 Thread ma...@mendelu.cz
This is the definition of ic2 from http://www.math.utexas.edu/pipermail/maxima/2009/015655.html 312 ic2(soln,xa,ya,dya):= 313block([programmode:true,backsubst:true,singsolve:true,temp, %k2,%k1], 314 noteqn(xa), noteqn(ya), noteqn(dya), 315 boundtest('%k1,%k1),

[sage-support] Re: desolve - my missunderstanding or a bug in Sage?

2009-10-03 Thread ma...@mendelu.cz
On 3 říj, 23:22, ma...@mendelu.cz ma...@mendelu.cz wrote: I have not enought skill in Python, Sage, hg and related thinks. Is there any person interested in the problem, which sould like to try this? The following code works in Sage y=function('y',x) k1,k2=var('k1 k2') x0,y0,y1=0,1,2#

[sage-support] Re: desolve

2008-02-18 Thread Alex Ghitza
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Thanks, David, that does indeed explain it. How hard would it be to have Sage figure out if the ODE is nonlinear and return an error instead of a fake solution? Alex David Joyner wrote: | The DE is not linear. The docstring (type ?desolve) says: