2008/9/4 David Philp <[EMAIL PROTECTED]>: > > > On 04/09/2008, at 8:22 PM, agi wrote: > >> >> Hi, >> I want to check if a number is set to infinity or NaN. So I tried this >> if-statement: >> >> if x!=infinity: >> print x >> >> But this doesn't work when x=a/b with a very small b, so that x >> becomes infinity. >> (I'm using SAGE Version 3.0.1) > > If x = 1.0/0 and y = -1.0/0, then > (1) x.is_infinity() and y.is_infinity() are both True > (2) x == y is False. > (3) x.is_NaN() is False. > > Have a look at > http://sagemath.org/doc/ref/module-sage.rings.real-double.html > (search for "is_infinity") (There may be a better reference.) >
I think this is better: http://sagemath.org/doc/ref/module-sage.rings.real-mpfr.html since RDF (double precision reals) is deprecated. Again, look for is_infinity. John Cremona > D > > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
