From: Siep Korteling <s.korteling@...>
Date: 2010-03-03T02:27:31+09:00
Subject: Re: Increase significant digits in Float

Xavier Noria wrote:
> On Tue, Mar 2, 2010 at 5:00 PM, Jason Lillywhite
> <jason.lillywhite@gmail.com> wrote:
> 
>> Thank you! I forgot that IRB is returning a truncated string to the
>> screen.
> 
> That 15 is hard-coded in the definition of Float#to_s.

Yes, and exposing more digits is not accurate:

puts "%.70f"%(4.005 / 7)
#=>0.5721428571428571752122138605045620352029800415039062500000000000000000
require 'bigdecimal'
a = BigDecimal.new("4.005")
b = a/7
puts b
#=>0.572142857142857142857143E0
p b.precs
#=>[24, 32]


#first number is the number of significant digits in b; the second 
number is the maximum precision my system can handle (not sure about 
this). The float is bogus  after the 16th digit.

hth,

Siep
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