From: Todd Benson <caduceass@...>
Date: 2007-07-17T21:12:48+09:00
Subject: Re: Force calculation result to BigDecimal

On 7/17/07, Robert Klemme <shortcutter@googlemail.com> wrote:

> Hm....  I don't think this is a fix because once you have a float you
> lost all the precision.

Can you elaborate on this?  I was under the impression that converting
to BigDecimal before arithmetic operations would get around this.
Using
class Float
  def big; BigDecimal(self.to_s); end
end
irb > Math::PI.big * 2.0
=> 6.283185307178
irb > Math::PI.big * 2.0.big
=> #<BigDecimal:81c2b88,'0.6283185307 17958E1',20(36)>

> A better fix is probably to change #coerce to
> work properly. Another solution is to make sure all values are
> converted to BD before starting the calculation.

This would be the best solution (maybe through #induced_from?), but I
don't know how to do it.

> Note, that BigDecimal is returned when working with integers.

Todd