On 30 Jun 2010, at 09:35, Rimas M. wrote: > So question is, what is the most efficient (performance side) and > simplest (coding side) way to compare those bastards? > > At the moment I am thinking about: > > a) BOOL _floatsOrDoublesAreEqual = ( (float)C.x == (float)D.x); > > b) BOOL _floatsOrDoublesAreEqual = ( fabs(C.x - D.x) <= _epsilon ); , > where _epsilon is something like 0.0001.
fabs is the right way to do this in most cases, *but* with co-ordinate values it may be that you are actually more interested in the distance of one point from the other---i.e. you might in fact be interested in CGFloat dx = C.x - D.x, dy = C.y - D.y; BOOL pointsAreEqual = (dx * dx + dy * dy) < epsilonSquared; It rather depends on what you want, and that's going to differ from one application to another. Kind regards, Alastair. -- http://alastairs-place.net _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
