From: Ara.T.Howard@...
Date: 2004-10-16T00:14:30+09:00
Subject: Re: Rounding to X digits

--8323328-351216961-1097852869=:30612
Content-Type: MULTIPART/MIXED; BOUNDARY="8323328-351216961-1097852869=:30612"

  This message is in MIME format.  The first part should be readable text,
  while the remaining parts are likely unreadable without MIME-aware tools.

--8323328-351216961-1097852869=:30612
Content-Type: TEXT/PLAIN; charset=X-UNKNOWN; format=flowed
Content-Transfer-Encoding: QUOTED-PRINTABLE

On Fri, 15 Oct 2004, trans.  (T. Onoma) wrote:

> On Thursday 14 October 2004 01:55 pm, Markus wrote:
> | Here's mine (with a few extras):
> |
> | class Numeric
> |     def iff(cond)
> |         cond ? self : self-self
> |         end
> |     def to_the_nearest(n)
> |         n*(self/n).round
> |         end
> |     def aprox(x,n=3D0.001)
> |         (to_the_nearest n) =3D=3D (x.to_the_nearest n)
> |         end
> |     def at_least(x); (self >=3D x) ? self : x; end
> |     def at_most(x);  (self <=3D x) ? self : x; end
> |     end
> |
>
> |     def to_the_nearest(n)
> |         n*(self/n).round
> |         end
>  def round_to_nearest( n=3D0.01 )
> =C2=A0=C2=A0  (self * (1/n)).round.to_f / (1/n)
> =C2=A0=C2=A0end
>
> For some reason they don't give the exact same answer. Try an edge case.
>
>  irb(main):066:0> 0.1 * (134.45/0.1).round
>  =3D> 134.4
>  irb(main):067:0> (134.45 * (1/0.1)).round.to_f / (1/0.1)
>  =3D> 134.5

   jib:~/eg/ruby > cat truncate.rb
   class Float
     def truncate sd =3D 2
       i =3D self.to_i
       prec =3D 10 ** sd
       fraction =3D (i.zero? ? self : (self / i) - 1)
       i + (fraction * prec).to_i / prec.to_f
     end
   end

   p(0.1 * (134.45/0.1).truncate)                   #=3D> 134.4
   p((134.45 * (1/0.1)).truncate.to_f / (1/0.1))    #=3D> 134.4

   jib:~/eg/ruby > ruby truncate.rb
   134.4
   134.4

regards.

-a
--
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D
| EMAIL   :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
| PHONE   :: 303.497.6469
| When you do something, you should burn yourself completely, like a good
| bonfire, leaving no trace of yourself.  --Shunryu Suzuki
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D
--8323328-351216961-1097852869=:30612--
--8323328-351216961-1097852869=:30612--