Hi All,
I've been digging around in src/nmath and have discovered that there are
two sets of "machine constants" in bessel_l.c and bessel_j.c which
have
different values:
bessel_i.c: static double ensig = 1e16;
bessel_i.c: static double rtnsig = 1e-4;
bessel_i.c: static double enmten = 8.9e-308;
bessel_i.c: static double enten = 1e308;
bessel_j.c: static double ensig = 1e17;
bessel_j.c: static double rtnsig = 1e-4;
bessel_j.c: static double enmten = 1.2e-37;
bessel_j.c: static double enten = 1e38;
According to the comments heading the files, the first set is correct for
IEEE Double-Precision hardware (the comments give the same values for
these parameters in each file):
Approximate values for some important machines are:
it NSIG ENTEN ENSIG
[...]
IEEE (IBM/XT,
SUN, etc.) (D.P.) 53 16 1.0D+308 1.0D+16
[...]
RTNSIG ENMTEN XLARGE
[...]
IEEE (IBM/XT,
SUN, etc.) (D.P.) 1.0E-4 8.90D-308 1.0D+4
[...]
Is there some reason for using different values in bessel_j.c than in
bessel_l.c? Or is this just a bug? ;^)
-Greg
PS: Where is DBL_EPSILON defined, and what is its value?
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !) To:
r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
