Hi, What is gp? Is it some software that can compute with arbitary precision?
I write some program with gmp, and now I have to admit that 1.48E10 is the more accurate answer now. It is awkward that the library sinl() function, which works on long double data, has a less accuracy than sin()... On Thu, Jun 17, 2010 at 10:59 AM, Brian Gough <[email protected]> wrote: > At Wed, 16 Jun 2010 14:16:47 +0200, > Luciano Ribichini wrote: > > I am studying the GSL with the goal of learning to avoid pitfall in > computer science. > > I found a very nice article by Monniaux on the arxiv server cs/0701192 > and on page 18 > > I found a very nice check of the sinus function. > > > > y=sin(14885392687.0) > > > > I wrote a very small program, and I got the wrong result > > > > y=1.48E-10 > > > > Thanks for the email. What sin function do you use - gsl_sf_sin? > > This is what I get in Pari with 64-digits of precision: > > $ gp > ? default(realprecision,64) > %1 = 64 > > ? 14885392687.0/Pi > %3 = 4738167652.000000000047103786916527482860432105403202244461035583 > ? 14885392687.0-4738167652*Pi > %4 = 1.479809109332217594562699619166045849796144302348 E-10 > ? sin(14885392687.0-4738167652*Pi) > %5 = 1.479809109332217594557298722864333901077382651758 E-10 > > Maybe you can explain the difference from the paper for me. > > -- > Brian Gough > > > _______________________________________________ > Bug-gsl mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/bug-gsl > _______________________________________________ Bug-gsl mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-gsl
