Hi.
On Sat, Jan 15, 2011 at 12:48:45PM -0500, Phil Steitz (JIRA) wrote:
>
> [
> https://issues.apache.org/jira/browse/MATH-475?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12982118#action_12982118
> ]
>
> Phil Steitz edited comment on MATH-475 at 1/15/11 12:48 PM:
> ------------------------------------------------------------
>
> Very interesting example. How do you come up with this stuff, Sebb? :)
>
> I tend to agree with Gilles' view that if if a and b are not distinguishable
> as doubles, we don't really have any confidence in the value of abs(a - b),
> so the short-circuit in the current code is better. I would say just update
> the javadoc to make say something like
>
> "Returns true if the values are indistinguishable as doubles or the
> difference between them is within the range of allowed error (inclusive)."
>
> was (Author: psteitz):
> Very interesting example. How do you come up with this stuff, Sebb? :)
>
> I tend to agree with Gilles' view that if if a and b are not distinguishable
> as doubles, we don't really have any confidence in the value of abs(a - b),
> so the short-circuit in the current code is better. I would say just update
> the javadoc to make say something like
>
> "Returns true if there is no double value strictly between the arguments or
> the difference between them is within the range of allowed error (inclusive)."
Just to be sure that we agree on the semantics of "equals": The latter
description ("there is no double value strictly between the arguments")
seems more representative of the code. Indeed, 2 successive floating point
numbers _are_ distinguishable, but "equals" will nevertheless return true on
the ground that any real number within the interval could be mapped to
either of the two floating point numbers.
Gilles
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