Re: Laguerre Polynomial overflow...

["Robert G. Brown" <rgb at phy dot duke dot edu>]

On Wed, 2 Oct 2002, Gert Van den Eynde wrote:

> 
> Dear Robert,

> I cannot reproduce this using gsl-1.2 (my own compilation) on a SuSE
> 8.0 linux machine. Could you try to compile and run the attached program
> and see if that fails too?

Before starting to mess with the internal code I upgraded to the gsl 1.1
I had available in the RH 7.3 RPM set.  It already worked at that point.
Obviously little brownies were at work removing odd convergence/overflow
bugs in between...;-)

The moral, I suppose, is that I should make sure I'm using the latest
version before filing a bug report.  I'm a Bad Dog...

I appreciate it, though, and apologize for wasting your time.

I'll definitely compile and work through 1.2 before worrying about my
NEXT gsl problem -- the lack of (visible) adaptive stepsizes in the gsl
ode solvers.  Thus far I've had to solve on a very fine grid to get
decent accuracy (bound state eigensolutions integrated out from the
origin spend a bit of time crossing the axis where they oscillate and
eventually become stiff), but from the manual it looks like some
adaptive stepsize routines have already made their way into the later
revisions.  I can't wait to try them out.

BTW, the GSL is a fabulous toolset and I don't mean to sound critical at
all.  NR sucks (yes, I've read the rant, and then there is the
strangulation noose -- I mean "copyright").  I'd like to contribute, if
I ever have the chance.  For example, I have (somewhere, I'd have to dig
it out) a C translation of Forsythe, Malcom and Moler's "QUANC8" (8
panel Newton-Cotes quadrature) if that is of interest.  I'm not really a
computer scientist, but I've done a lot of numerical computations over
the last decade or two.  The other thing I might be able to contribute
is at least simple genetic optimization algorithms and (if I could
figure out how to frame them) neural network algorithms, as this is one
of the things I do.

   rgb

-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb@phy.duke.edu