[Ecls-list] How might this elliptic_e issue on SPARC hardware with ECL be debugged?
Dr. David Kirkby
david.kirkby at onetel.net
Mon Aug 10 07:42:44 UTC 2009
You probably see my previous posts on the fact that elliptic_e is giving
incorrect results on SPARC hardware using ECL. If not,
http://sagetrac.org/sage_trac/ticket/6716
has the details.
Can anyone who knows the internals of Maxima tell me what standard
libraries supplied with Solaris the functions 'elliptic_e' might be
expected to call?
Looking in a maths book, I see some formula with sin() in them,
suggesting an incorrect result from sin(x) might mess the computation of
an elliptic integral. A few quick checks with sin() on Sage showed no
obvious differences from those computed in Mathematica.
Is there anything else that could be suspected, and so narrow down the
list of possible causes somewhat?
Sage can certainly be eliminated, as the problem is seen when I call
Maxima directly. Things that can't be totally eliminated, but some are
very unlikly, include:
* Hardware fault on the particular machine.
* Design flaw in Sun UltraSPARC CPU (remember the Pentium floating point
bug, which must have cost Intel a fortune?)
* ECL
* Solaris library bug
* Maxima
* gcc
* I screwed up compiling Maxima or ECL.
I hope to eliminate the possibility of a hardware fault by copying the
binaries to another Sun.
I believe ECL will build with Sun's compiler, so I can try to eliminate
gcc as the culprit.
Can anyone with a better maths background suggest other ways the
possible range of issues could be narrowed down?
More information about the ecl-devel
mailing list