Bug #4656: Float#to_s can produce too many digits

• Status: Rejected
• Assignee: mrkn (Kenta Murata)
• Target version: -
• ruby -v: ruby 1.9.3dev (2011-05-09 trunk 31491) [x86_64-darwin10.7.0]

[mrkn (Kenta Murata)]

In trunk, Float#to_s can produce too many digits.

$ ./miniruby -ve 'puts Float::DIG, 3970 / 3000.0'
ruby 1.9.3dev (2011-05-09 trunk 31491) [x86_64-darwin10.7.0]
15
1.3233333333333333

In the above example, Float::DIG is 15, so the number of significant digits is at most 16.
However, the indefinite 17th digit is produced.

1.9.2 also has this issue.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Rejected

Because they are different values.

$ ruby -e 'p 1.323333333333333 == 3970 / 3000.0'
false
$ ruby -e 'p 1.3233333333333333 == 3970 / 3000.0'
true