On Mon, May 28, 2012 at 06:44:42PM -0500, Stephen Montgomery-Smith wrote: > On 05/28/2012 06:30 PM, Steve Kargl wrote: > > > > >>From clog.c in http://www.netlib.org/cephes/c9x-complex > > > >double complex > >ccosh (z) > > double complex z; > >{ > > double complex w; > > double x, y; > > > > x = creal(z); > > y = cimag(z); > > w = cosh (x) * cos (y) + (sinh (x) * sin (y)) * I; > > return (w); > >} > > > >See math_private.h about the above. > > > > I looked in math_private.h - I presume you meant > lib/msun/src/math_private.h. I wasn't able to find anything about ccosh > there. > > I think that for a rough and ready ccosh, this is high enough quality > for a math/cephes port.
That's the problem. It is not acceptable (imo). The comment in math_private.h that is relevant is /* * Inline functions that can be used to construct complex values. * * The C99 standard intends x+I*y to be used for this, but x+I*y is * currently unusable in general since gcc introduces many overflow, * underflow, sign and efficiency bugs by rewriting I*y as * (0.0+I)*(y+0.0*I) and laboriously computing the full complex product. * In particular, I*Inf is corrupted to NaN+I*Inf, and I*-0 is corrupted * to -0.0+I*0.0. */ Those wrong +-0 mean you may up end up on the worng riemann sheet, and that NaN propagates. -- Steve _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
