This is the mail archive of the
gsl-discuss@sources.redhat.com
mailing list for the GSL project.
Re: GSL 1.4: BUG #8 [rk8pd.c]
- From: Luc Maisonobe <Luc dot Maisonobe at free dot fr>
- To: gsl-discuss at sources dot redhat dot com
- Date: Sat, 08 Nov 2003 08:00:10 +0100
- Subject: Re: GSL 1.4: BUG #8 [rk8pd.c]
Hello,
The remaining problem is still the same as one year ago: the comments
say the method is an 8(9) method (i.e. extrapolation beeing of order 8
and error estimation of order 9), but it is really an 8(7) method.
Despite I think nobody is interested anymore, I promised to check the
coefficients of the method, so here are my results.
The maximal error in rk8pd.c is about 3.92e-17.
The maximal error in rksuite.f is about 4.49e-29.
These values were computed by picking two coefficients from rksuite
(c(9) and a(8,4)) as the remaining free parameters of the model,
transforming them into rational numbers by continued fractions method
and using them to solve exactly all the equations of conditions and all
the additional equations from the article. The exact result is available
in http://www.spaceroots.org/software/rkcheck/DormandPrinceRKsuite.xml
Luc