# Bug in Float? (was: NaN Error) **URL:** \ **Category:** Ruby\ **Created:** [April 17, 2007, 8:42pm UTC](https://www.ruby-forum.com/t/bug-in-float-was-nan-error/92287 "2007-04-17T20:42:12Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\ **Post date:** [April 17, 2007, 8:42pm UTC](https://www.ruby-forum.com/t/bug-in-float-was-nan-error/92287/1 "2007-04-17T20:42:12Z")
I ran across some peculiar behavior yesterday when working with large floating point values. Here is a small script that demonstrates the behavior. My question is, is this the expected behavior or is this a bug in Float? > cat float\_bug.rb > puts "ruby #{RUBY\_VERSION} " + > "(#{RUBY\_RELEASE\_DATE} patchlevel #{RUBY\_PATCHLEVEL}) " + > “[#{RUBY\_PLATFORM}]” puts “Float::MAX = #{Float::MAX}” puts “1.0e+300 = #{1.0e+300}” puts “1.0e+301 = #{1.0e+301}” puts “1.0e+308 = #{1.0e+308}” puts “1.0e+700 = #{1.0e+700}” # EOF When I run this script on my Windows machine, it produces the output I would expect – i.e. numbers above Float::MAX are “Infinity” and numbers below Float::MAX are valid floating point numbers. > ruby -w float\_bug.rb > ruby 1.8.5 (2006-12-25 patchlevel 12) [i386-cygwin] > Float::MAX = 1.79769313486232e+308 > 1.0e+300 = 1.0e+300 > 1.0e+301 = 1.0e+301 > 1.0e+308 = 1.0e+308 > 1.0e+700 = Infinity Now, when I run the exact same script on a Solaris machine, some odd things start to happen > ruby -w float\_bug.rb > ruby 1.8.5 (2006-12-25 patchlevel 12) [sparc-solaris2.8] > Float::MAX = 1.79769313486232e+308 > 1.0e+300 = 1.0e+300 > 1.0e+301 = NaN > 1.0e+308 = NaN > 1.0e+700 = 8.55180271847103e+116 Whey are valid floats being treated as NaN? Better yet, why does 1.0e+700 get evaluated to 8.5518027e+116? Once more on the Windows 1-click installed version of Ruby. > ruby -w float\_bug.rb > ruby 1.8.6 (2007-03-13 patchlevel 0) [i386-mswin32] > Float::MAX = 1.79769313486232e+308 > 1.0e+300 = 1.0e+300 > 1.0e+301 = NaN > 1.0e+308 = NaN > 1.0e+700 = 1.0e+189 Any thoughts on this one? I encourage you to copy the float\_bug.rb script and try it out for yourself. Blessings, TwP ---
**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\ **Post date:** [April 17, 2007, 9:25pm UTC](https://www.ruby-forum.com/t/bug-in-float-was-nan-error/92287/2 "2007-04-17T21:25:20Z")
$ ruby float\_bug.rb ruby 1.8.5 (2006-08-25) [i486-linux] Float::MAX = 1.79769313486232e+308 1.0e+300 = 1.0e+300 1.0e+301 = 1.0e+301 1.0e+308 = 1.0e+308 1.0e+700 = 1.02189775487683e+36 ---
**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\ **Post date:** [April 17, 2007, 9:46pm UTC](https://www.ruby-forum.com/t/bug-in-float-was-nan-error/92287/3 "2007-04-17T21:46:21Z")
On Apr 17, 11:41 am, “Tim P.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Once more on the Windows 1-click installed version of Ruby. > > > ruby -w float\_bug.rb > > ruby 1.8.6 (2007-03-13 patchlevel 0) [i386-mswin32] > Float::MAX = 1.79769313486232e+308 > 1.0e+300 = 1.0e+300 > 1.0e+301 = NaN > 1.0e+308 = NaN > 1.0e+700 = 1.0e+189 Further, (Windows, 1-click), same version: C:\>ruby -v ruby 1.8.6 (2007-03-13 patchlevel 0) [i386-mswin32] C:\>irb -v irb 0.9.5(05/04/13) C:\>irb irb(main):001:0\> 1.0e+800 =\> 1.0e+289 irb(main):002:0\> 1.0e+900 =\> NaN irb(main):003:0\> 1.0e+1000 =\> NaN irb(main):004:0\> 1.0e+1100 (irb):4: warning: Float 1.0e+1100 out of range =\> Infinity ---
**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\ **Post date:** [April 18, 2007, 3:42am UTC](https://www.ruby-forum.com/t/bug-in-float-was-nan-error/92287/4 "2007-04-18T03:42:51Z")
Hi, At Wed, 18 Apr 2007 03:41:22 +0900, Tim P. wrote in [ruby-talk:248272]: > I ran across some peculiar behavior yesterday when working with large > floating point values. Here is a small script that demonstrates the > behavior. My question is, is this the expected behavior or is this a > bug in Float? Thank you, fixed now. ---
**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\ **Post date:** [April 17, 2007, 11:21pm UTC](https://www.ruby-forum.com/t/bug-in-float-was-nan-error/92287/5 "2007-04-17T23:21:38Z")
On Apr 17, 12:41 pm, “Tim P.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > numbers below Float::MAX are valid floating point numbers. > Now, when I run the exact same script on a Solaris machine, some odd > > 1.0e+301 = NaN > 1.0e+308 = NaN > 1.0e+700 = 1.0e+189 > > Any thoughts on this one? I encourage you to copy the float\_bug.rb > script and try it out for yourself. > > Blessings, > TwP On OS X 10.4.9 mvb:~ cms$ ruby float\_bug.rb ruby 1.8.6 (2007-03-13 patchlevel 0) Float::MAX = 1.79769313486232e+308 1.0e+300 = 1.0e+300 1.0e+301 = NaN 1.0e+308 = NaN 1.0e+700 = 0.0 And my Xubuntu box (pre-RUBY\_PATCHLEVEL apparently): ruby 1.8.4 (2005-12-24)[i486-linux] Float::MAX = 1.79769313486232e+308 1.0e+300 = 1.0e+300 1.0e+301 = 1.0e+301 1.0e+308 = 1.0e+308 1.0e+700 = 0.0 ---
**Author:** ![timperrett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c5a1d2/32.png) [@timperrett](https://www.ruby-forum.com/u/timperrett)\ **Post date:** [April 18, 2007, 4:57pm UTC](https://www.ruby-forum.com/t/bug-in-float-was-nan-error/92287/6 "2007-04-18T16:57:54Z")
On 4/17/07, Nobuyoshi N. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Thank you very much, Nobu. TwP