[Proj] Re: Re: Proj4 Bug (rtodms)
Gerald I. Evenden
gerald.evenden at verizon.mail
Thu Nov 9 17:58:12 EST 2006
On Thursday 09 November 2006 4:44 pm, Glynn Clements wrote:
> > I am still suspicious of the setting of the FPU's rounding flag.
> > This does raise in my mind: what should the default state of the rounding
> > flag be?
> Appendix F of the C99 standard requires round-to-nearest during
> translation (F.7.2) and at program startup (F.7.3). However, the
> standard doesn't require an implementation to conform to appendix F
> unless it indicates conformance by defining the macro
I gave up getting the standards years ago as they were getting to damn
expensive so I rely on Harbison & Steele, v.5. But I am glad to see that
there is a (tentative) default setting.
> In any case, 240.0/60.0 should be exactly equal to 4.0 regardless of
> the rounding mode; anything else is a bug. The rounding mode is only
> relevant if a result cannot be represented exactly.
All this would be irrelevant if we all got 64 bit machines and could do this
in integer arithmetic.
> Contrary to widespread belief, the FPU doesn't get the least
> significant bits of a result from /dev/random ;)
Oh? Damn! I learn something every day. :-)
I really did learn something: I didn't know there was a /dev/random
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist
More information about the Proj