# \[Bug #1720\] \[NaN\] == \[NaN\] $B$,(B true $B$K$J$k(B

**URL:** <https://www.ruby-forum.com/t/bug-1720-nan-nan-b-b-true-b-k-j-k-b/171493>\
**Category:** Development\
**Created:** [July 3, 2009, 2:44pm UTC](https://www.ruby-forum.com/t/bug-1720-nan-nan-b-b-true-b-k-j-k-b/171493 "2009-07-03T14:44:45Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![tadayoshi\_funaba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/f0a364/32.png) [@tadayoshi\_funaba](https://www.ruby-forum.com/u/tadayoshi_funaba)\
**Post date:** [July 3, 2009, 2:44pm UTC](https://www.ruby-forum.com/t/bug-1720-nan-nan-b-b-true-b-k-j-k-b/171493/1 "2009-07-03T14:44:45Z")

</div>

Bug #1720: [NaN] == [NaN] e$B$,e(B true e$B$K$J$ke(B  
[http://redmine.ruby-lang.org/issues/show/1720](http://redmine.ruby-lang.org/issues/show/1720)

e$B5/I\<\<Te(B: tadayoshi funaba  
e$B%9%F!\<%?%9e(B: Open, e$BM%@hEYe(B: Normal  
Target version: 1.9.x  
ruby -v: ruby 1.9.2dev (2009-07-03 trunk 23945) [i686-linux]

NaN = 0.0/0  
[NaN] == [NaN] e$B$,e(B true e$B$K$J$j$^$9$,!"e(B

NaN == NaN #=\> false  
[1] == [1.0] #=\> true

e$B$H$$$&7k2L$+$i$9$k$H$\*$+$7$$$h$&$K;W$$$^$9!#e(B

---

<div class="post-metadata">

**Author:** ![tadayoshi\_funaba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/f0a364/32.png) [@tadayoshi\_funaba](https://www.ruby-forum.com/u/tadayoshi_funaba)\
**Post date:** [July 4, 2009, 6:15pm UTC](https://www.ruby-forum.com/t/bug-1720-nan-nan-b-b-true-b-k-j-k-b/171493/2 "2009-07-04T18:15:01Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:38725] [Bug #1720] [NaN] == [NaN] e$B$,e(B  
true e$B$K$J$ke(B”  
on Fri, 3 Jul 2009 21:43:24 +0900, tadayoshi funaba  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|NaN = 0.0/0  
|[NaN] == [NaN] e$B$,e(B true e$B$K$J$j$^$9$,!"e(B  
|  
|NaN == NaN #=\> false  
|[1] == [1.0] #=\> true  
|  
|e$B$H$$$&7k2L$+$i$9$k$H$\*$+$7$$$h$&$K;W$$$^$9!#e(B

e$B3N$+$K!#e(Brb\_equal()e$B$,N\>JU$,F1$8%_%V%8%'%/%H$N$H$-$K%a%=%C%I8Fe(B  
e$B$S=P$7$r9T$o$:$K??$rJV$7$F$$$k$;$$$G$9$M!#e(BNaNe$B$H$$$&$N$O!"e(B  
equal?e$B$,@.N)$7$F$be(B==e$B$,@.N)$7$J$$$H$$$&FC0[$J%_%V%8%'%/%H$G$"e(B  
e$B$k$?$a$K$3$NLdBj$,H/@8$7$F$$$^$9!#e(B

e$B$H$O$$$(!“$3$s$JFC\<l$JNc$N$?$a$KF1CM@-%A%'%C%/$rCY$/$7$?$/$Je(B  
e$B$$$7!”:$$C$?$b$N$G$9!#e(B

---

<div class="post-metadata">

**Author:** ![tadayoshi\_funaba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/f0a364/32.png) [@tadayoshi\_funaba](https://www.ruby-forum.com/u/tadayoshi_funaba)\
**Post date:** [July 4, 2009, 6:32pm UTC](https://www.ruby-forum.com/t/bug-1720-nan-nan-b-b-true-b-k-j-k-b/171493/3 "2009-07-04T18:32:32Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:38734] Re: [Bug #1720] [NaN] == [NaN]  
e$B$,e(B true e$B$K$J$ke(B”  
on Sun, 5 Jul 2009 01:14:16 +0900, Yukihiro M.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

||NaN = 0.0/0  
||[NaN] == [NaN] e$B$,e(B true e$B$K$J$j$^$9$,!"e(B  
||  
||NaN == NaN #=\> false  
||[1] == [1.0] #=\> true  
||  
||e$B$H$$$&7k2L$+$i$9$k$H$_$+$7$$$h$&$K;W$$$^$9!#e(B  
|  
|e$B3N$+$K!#e(Brb\_equal()e$B$,N\>JU$,F1$8%_%V%8%‘%/%H$N$H$-$K%a%=%C%I8Fe(B  
|e$B$S=P$7$r9T$o$:$K??$rJV$7$F$$$k$;$$$G$9$M!#e(BNaNe$B$H$$$&$N$O!"e(B  
|equal?e$B$,@.N)$7$F$be(B==e$B$,@.N)$7$J$$$H$$$&FC0[$J%\*%V%8%’%/%H$G$"e(B  
|e$B$k$?$a$K$3$NLdBj$,H/@8$7$F$$$^$9!#e(B

e$B9M$($i$l$kBP=h$Oe(B

(1) NaN == NaN e$B$be(B true e$B$K$9$ke(B  
e$B0l4S@-$O$"$k$,e(B NaN e$B$NK\Mh$N5sF0$G$O$J$$e(B  
(2) rb\_equal()e$B$G$^$:e(Bequal?e$B$G$N%A%'%C%/$r$d$a$ke(B  
e$B@-G=$,Nt2=$9$k$N$GHr$1$?$$e(B  
(3) rb\_equal()e$B$Ge(BT\_FLOATe$B$rFCJL07$$e(B  
2e$B$[$I$G$O$J$$$K$7$F$b@-G=Nt2=$,5$$K$J$ke(B  
e$BFCJL07$$$O8e2y$9$k$3$H$,B?$$e(B  
(4) e$B$3$N$^$^!#$3$l$ONc30E\*$J%1!\<%9$H$9$ke(B

e$B$/$i$$$G$7$g$&$+!#e(B

e$B;d\<+?H$O!"$I$l$,NI$$$H$$$&0U8+$r8=;~E@$G$O;}$?$J$$$N$G$9$,!"e(B  
e$B$I$l$,9%$-$+$H8@$o$l$l$P!"e(B(1)e$B$,9%$-$G$9!#e(B

---

<div class="post-metadata">

**Author:** ![tadayoshi\_funaba](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/f0a364/32.png) [@tadayoshi\_funaba](https://www.ruby-forum.com/u/tadayoshi_funaba)\
**Post date:** [July 13, 2009, 2:15pm UTC](https://www.ruby-forum.com/t/bug-1720-nan-nan-b-b-true-b-k-j-k-b/171493/4 "2009-07-13T14:15:02Z")

</div>

e$B$1$$$8$e!w$$$7$D$+$G$9e(B.

In [ruby-dev:38735] the message: “[ruby-dev:38735] Re: [Bug #1720]  
[NaN] == [NaN] e$B$,e(B true e$B$K$J$ke(B”, on Jul/05 01:31(JST)  
Yukihiro  
Matsumoto writes:

> e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

> (1) NaN == NaN e$B$be(B true e$B$K$9$ke(B  
> e$B0l4S@-$O$"$k$,e(B NaN e$B$NK\Mh$N5sF0$G$O$J$$e(B  
> (2) rb\_equal()e$B$G$^$:e(Bequal?e$B$G$N%A%’%C%/$r$d$a$ke(B  
> e$B@-G=$,Nt2=$9$k$N$GHr$1$?$$e(B  
> (3) rb\_equal()e$B$Ge(BT\_FLOATe$B$rFCJL07$$e(B  
> 2e$B$[$I$G$O$J$$$K$7$F$b@-G=Nt2=$,5$$K$J$ke(B  
> e$BFCJL07$$$O8e2y$9$k$3$H$,B?$$e(B  
> (4) e$B$3$N$^$^!#$3$l$ONc30E\*$J%1!\<%9$H$9$ke(B

> e$B;d\<+?H$O!"$I$l$,NI$$$H$$$&0U8+$r8=;~E@$G$O;}$?$J$$$N$G$9$,!"e(B  
> e$B$I$l$,9%$-$+$H8@$o$l$l$P!"e(B(1)e$B$,9%$-$G$9!#e(B

e$B$o$?$7$be(B, (1)e$B$N$h$&$J5$$,$7$^$9e(B.

e$B$H$$$&$+e(B, (1’)e$B$G$9$+e(B:

(1’)  
nan1 = 0.0/0  
nan2 = 0.0/0

e$B$H$7$Fe(B,

nan1 == nan1 =\> true  
nan1 == nan2 =\> false

e$B8=9T$G$Oe(B,

nan1.equal?(nan1)

e$B$J$N$Ke(B,

nan1 == nan1 =\> false

e$B$H$J$k$N$Oe(B,e$B%_%V%8%’%/%H;X8~E_$K$+$J$j5$J,$N0-$$;EMM$@$H;W$$$^$9e(B.  
nan1  
e$B$He(Bnan1e$B$NCM$O$d$O$jF1$8$@$H$7$F$h$$$H;W$$$^$9e(B.

> ```
> e$B0l4S@-$O$"$k$,e(B NaN e$B$NK\Mh$N5sF0$G$O$J$$e(B
> 
> ```

e$B$H$"$j$^$9$,e(B, e$B$=$l$K4X$7$F$Oe(B nan1 == nan2 =\> false  
e$B$K$J$l$PLdBj$J$$$-e(B  
e$B$,$7$^$9e(B.

\_\_  
----------------------------------------------------\>\> e$B@PDMe(B  
e$B7=\<ye(B \<\<—  
----------------------------------\>\> e-mail: removed\_email\_address@domain.invalid \<\<—