Thanks for taking the time to explain, Jason. 2009/5/7 Jason Grout <jason-s...@creativetrax.com>: > > John Cremona wrote: >> 2009/5/7 Nick Alexander <ncalexan...@gmail.com>: >>>> sage:RIF( 3 , 3.2 ) >>>> 4.±1 >>> -2 to unicode or whatever lets you type $\pm$. >>> >>> As for the fact that 4.? is confusing to people who know nothing about >>> sage, that does not concern me in the slightest. I find lots of >>> things that I know nothing about confusing! >> >> Me too, but I have absolutely no idea why RIF(3,3.2) is anywhere near >> 4, so find this completely incomprehensible. Isn't it the interval >> from 3.0 to 3.2? >> >> I have never used the RIF, mainly because I cannot understand its output. > > > It's a compact notation for the interval: > > [4.0-1 .. 4.0+1] = [3.0 .. 5.0] > > The question mark just means the interval goes from the number with last > digit minus one to the number with last digit plus one. > > For example: > > 3.5? is the interval [3.4 .. 3.6] > > 3.293948? is the interval [3.293947 .. 3.293949] > > More documentation can be found by taking any element x of RIF and doing > x.str? > > You can change the default back to printing an explicit interval by doing: > > sage: sage.rings.real_mpfi.printing_style='brackets' > sage: RIF(3,3.2) > [3.0000000000000000 .. 3.2000000000000002] > sage: sage.rings.real_mpfi.printing_style='question' > sage: RIF(3,3.2) > 4.? >
Why is this not 3.1? From what you said earlier that means the interval between 3.1-0.1=3 and 3.1+0.1=3.2, doesn't it? John > > Carl, could you comment on the difference between these two cases? > > sage: RIF(3,3.199999999999999) > 3.1? > sage: RIF(3,3.1999999999999999) > 4.? > > Thanks, > > Jason > > > -- > Jason Grout > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
