On Sat, Jan 15, 2011 at 8:32 PM, Gilles Sadowski <gil...@harfang.homelinux.org> wrote: > 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. > Sorry I got the second version of the comment wrong. You are right that the current impl of equals identifies two consecutive doubles.
Phil > > Gilles > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
