From: nobu.nokada@...
Date: 2004-04-22T10:04:06+09:00
Subject: Re: 5.000...007.to_s => "5"

Hi,

At Thu, 22 Apr 2004 04:36:05 +0900,
Jeff Mitchell wrote in [ruby-talk:97924]:
> This fixes 1.000..7 but does not fix two other cases I didn't mention,
> 
> arda:~/cur/ruby> ./ruby -e 'puts 1.00000000000004.to_s'
> 1.00000000000004
> arda:~/cur/ruby> ./ruby -e 'puts 1.000000000000004.to_s'
> 1
> arda:~/cur/ruby> ./ruby -e 'puts 1.0000000000000004.to_s'
> 1.0
> arda:~/cur/ruby> ./ruby -e 'puts 1.99999999999999.to_s'
> 1.99999999999999
> arda:~/cur/ruby> ./ruby -e 'puts 1.999999999999999.to_s'
> 2
> arda:~/cur/ruby> ./ruby -e 'puts 1.9999999999999999.to_s'
> 2.0

Hmmm..., I didn't consider about upper boundary.


Index: numeric.c
===================================================================
RCS file: /cvs/ruby/src/ruby/numeric.c,v
retrieving revision 1.106
diff -u -2 -p -r1.106 numeric.c
--- numeric.c	14 Apr 2004 04:06:25 -0000	1.106
+++ numeric.c	22 Apr 2004 01:00:45 -0000
@@ -517,5 +517,5 @@ flo_to_s(flt)
 	else fmt = "%.16e";
     }    
-    else if ((d1 = modf(value, &d2)) == 0) {
+    else if ((d1 = modf(avalue, &d2)) <= 5.0e-15 || (1.0 - d1) <= 5.0e-15) {
 	fmt = "%.1f";
     }


-- 
Nobu Nakada