On Thu, 14 Mar 2019 at 04:41, Tom Lane <t...@sss.pgh.pa.us> wrote: > > Dean Rasheed <dean.a.rash...@gmail.com> writes: > > I'm amazed that jacana's asinh() returned -0 for an input of +0. > > Even more amusingly, it returns NaN for acosh('infinity'), cf > https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=jacana&dt=2019-03-14%2003%3A00%3A34 > > Presumably that means they calculated "infinity - infinity" at some > point, but why? >
Given the -0 result, I don't find that particularly surprising. I suspect lots of formulae would end up doing that without proper special-case handling upfront. It looks like that's the only platform that isn't POSIX compliant though, so maybe it's not worth worrying about. Regards, Dean