Re: INF behavior

> Agree with Derick, strictly speaking, in maths science, INF != INF. I disagree,based on quote from http://compilers.iecc.com/comparch/article/98-07-134: "Since a projective infinity doesn't have a sign, comparing a floating point value other than infinity to a projective infinity is unordered. However, a projective infinity is equal to itself." Hannes On 31 May 2011 21:39, Julien Pauli <jpauli@php.net> wrote: > Agree with Derick, strictly speaking, in maths science, INF != INF. > > But I dont care if PHP tells me than yes, because PHP is not designed > to solve high level maths problems :) > > Cheer, > > Julien.Pauli > > On Fri, May 27, 2011 at 4:48 PM, Derick Rethans <derick@php.net> wrote: > > On Thu, 26 May 2011, Scott MacVicar wrote: > > > >> On 26 May 2011, at 20:03, Philip Olson <philip@roshambo.org> wrote: > >> > >> > Hello geeks, > >> > > >> > A geek is needed to clarify PHP bug #45712. This is an edge case but > the test (bug45712.phpt) contains code similar to the following: > >> > > >> > <?php > >> > $inf = pow(0, -2); > >> > > >> > var_dump($inf); // float(INF) > >> > var_dump($inf == $inf); // bool(false) > >> > var_dump($inf === $inf); // bool(true) > >> > ?> > >> > > >> > That's how it's behaved since ~forever (AFAICT) and remains in > 5.3.7-dev, but PHP 5.4.0-dev changes behavior so both now return true. > >> > > >> > Is this is how we want it? And how should this be > documented/explained? > >> > >> I think I changes this :-) > >> > >> It didn't make sense that == and === produce different results. > >> > >> Though if someone has a better understanding of maths then we can fix > it. > > > > I think it does make sense. == is the equal operator, and INF is not > > equal to INF (just like SQL NULL is not equal to NULL). However, they > > are identical (like you can test in SQL with NULL IS NULL). > > > > cheers, > > Derick > > > > -- > > http://derickrethans.nl | > > http://xdebug.org > > Like Xdebug? Consider a donation: > > http://xdebug.org/donate.php > > twitter: @derickr and @xdebug > > > > -- > > PHP Internals - PHP Runtime Development Mailing List > > To unsubscribe, visit: http://www.php.net/unsub.php > > > > > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > >