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Re: T-Junctions re-visited
avatarMarch 20, 2013 10:26AM
Thinking about this some more, I think that what my current code is designed to do is reduce the number of occurences of floating point innaccuracies causing problems (with a bug of not checking the sign first). If the number is 1.03, that might end up in floating point as 1.02999999, or 1.03000001. Ideally, I'd like both of these to produce the same key value. My current code multiplies by 100 to produce 102.999999 or 103.000001, then adds .005, which produces 103.004999 or 103.005001, both of which get converted to 103. (I think this works out for negative numbers also, but the result would be -102, instead of -103 as normally expected. Given their use as keys, where the actual values don't really matter, this probably doesn't hurt anything.)

The expectation here is that LDraw files start out with fixed point coordinates, and very often, the transformed coordinate will also be very close to fixed point values (due to transformation matrices often being simple translations, or 90-degree increment rotations). So I wanted to prevent floating point innacuracies from separating two points from each other that were expected to be together.

It could well be that all of this was completely wrong-headed, and doesn't in fact do the job that it's intended to do when dealing with real-world parts.
SubjectAuthorViewsPosted
T-Junctions re-visited Travis Cobbs547March 11, 2013 10:38PM
Re: T-Junctions re-visited Tim Gould235March 11, 2013 11:31PM
Re: T-Junctions re-visited Roland Melkert204March 12, 2013 11:17AM
Re: T-Junctions re-visited Ben Supnik208March 12, 2013 11:17AM
Re: T-Junctions re-visited Roland Melkert204March 12, 2013 11:22AM
Re: T-Junctions re-visited Ben Supnik197March 12, 2013 11:32AM
Re: T-Junctions re-visited Roland Melkert188March 12, 2013 11:41AM
Re: T-Junctions re-visited Ben Supnik205March 12, 2013 11:55AM
Re: T-Junctions re-visited Roland Melkert199March 13, 2013 10:08AM
Re: T-Junctions re-visited Travis Cobbs233March 13, 2013 11:27AM
Re: T-Junctions re-visited Allen Smith236March 12, 2013 02:01PM
Re: T-Junctions re-visited Michael Heidemann212March 13, 2013 09:27AM
Re: T-Junctions re-visited Ben Supnik207March 13, 2013 10:37AM
Re: T-Junctions re-visited Tim Gould202March 13, 2013 02:31PM
Re: T-Junctions re-visited Michael Heidemann201March 13, 2013 03:42PM
Re: T-Junctions re-visited Michael Heidemann177March 17, 2013 04:35AM
Re: T-Junctions re-visited Ben Supnik174March 17, 2013 08:43AM
Re: T-Junctions re-visited Michael Heidemann179March 17, 2013 08:59AM
Re: T-Junctions re-visited Ben Supnik181March 17, 2013 09:02AM
Re: T-Junctions re-visited Magnus Forsberg181March 17, 2013 09:15AM
Re: T-Junctions re-visited Travis Cobbs200March 17, 2013 10:09PM
Re: T-Junctions re-visited Ben Supnik202March 18, 2013 07:30AM
Re: T-Junctions re-visited Travis Cobbs204March 18, 2013 10:57AM
Re: T-Junctions re-visited Ben Supnik207March 18, 2013 11:27AM
Re: T-Junctions re-visited Travis Cobbs201March 18, 2013 12:23PM
Re: T-Junctions re-visited Ben Supnik216March 18, 2013 01:41PM
Re: T-Junctions re-visited Roland Melkert209March 18, 2013 02:51PM
Re: T-Junctions re-visited Travis Cobbs196March 18, 2013 02:59PM
Re: T-Junctions re-visited Roland Melkert195March 18, 2013 03:41PM
Re: T-Junctions re-visited Ben Supnik209March 18, 2013 06:09PM
Re: T-Junctions re-visited Roland Melkert206March 19, 2013 11:38AM
Re: T-Junctions re-visited Ben Supnik215March 19, 2013 11:43AM
Re: T-Junctions re-visited Roland Melkert233March 19, 2013 07:07PM
Re: T-Junctions re-visited Travis Cobbs206March 19, 2013 10:13PM
Re: T-Junctions re-visited Tim Gould209March 20, 2013 03:56AM
Re: T-Junctions re-visited Travis Cobbs202March 20, 2013 10:13AM
Re: T-Junctions re-visited Ben Supnik187March 20, 2013 10:23AM
Re: T-Junctions re-visited Travis Cobbs201March 20, 2013 10:29AM
Re: T-Junctions re-visited Travis Cobbs194March 20, 2013 10:26AM
Re: T-Junctions re-visited Ben Supnik174March 20, 2013 11:18AM
Re: T-Junctions re-visited Ben Supnik191March 20, 2013 06:42AM
Re: T-Junctions re-visited Roland Melkert196March 20, 2013 11:36AM
Re: T-Junctions re-visited Philippe Hurbain191March 20, 2013 06:36AM
Re: T-Junctions re-visited Ben Supnik202March 20, 2013 06:58AM
Re: T-Junctions re-visited Allen Smith191March 20, 2013 09:08AM
Re: T-Junctions re-visited Roland Melkert210March 20, 2013 11:35AM
Re: T-Junctions re-visited Ben Supnik530March 20, 2013 11:50AM
Re: T-Junctions re-visited Michael Heidemann211March 18, 2013 03:54PM
Re: T-Junctions re-visited Roland Melkert204March 13, 2013 10:03AM
Re: T-Junctions re-visited Tim Gould191March 13, 2013 03:56PM
Re: T-Junctions re-visited Sergio Reano183March 13, 2013 03:51PM
Re: T-Junctions re-visited Roland Melkert239March 13, 2013 04:36PM
Re: T-Junctions re-visited Tim Gould198March 13, 2013 05:10PM
Re: T-Junctions re-visited Ben Supnik187March 14, 2013 08:17PM
Re: T-Junctions re-visited Tim Gould255March 14, 2013 08:41PM
Re: T-Junctions re-visited Ben Supnik234March 15, 2013 10:56AM
Re: T-Junctions re-visited Roland Melkert206March 15, 2013 11:36AM
Re: T-Junctions re-visited Ben Supnik193March 13, 2013 06:58PM
Re: T-Junctions re-visited Roland Melkert184March 13, 2013 07:27PM
Re: T-Junctions re-visited Ben Supnik175March 13, 2013 07:37PM
Re: T-Junctions re-visited Roland Melkert186March 13, 2013 07:59PM
Re: T-Junctions re-visited Ben Supnik210March 13, 2013 08:18PM
Re: T-Junctions re-visited Travis Cobbs226March 14, 2013 03:23PM
Re: T-Junctions re-visited Roland Melkert231March 14, 2013 03:34PM
Re: T-Junctions re-visited Tim Gould238March 14, 2013 03:41PM
Re: T-Junctions re-visited Roland Melkert210March 15, 2013 11:33AM
Re: T-Junctions re-visited Tim Gould174March 13, 2013 07:43PM
Re: T-Junctions re-visited Roland Melkert187March 13, 2013 08:08PM
Re: T-Junctions re-visited Tim Gould190March 13, 2013 08:18PM
Re: T-Junctions re-visited Ben Supnik237March 14, 2013 08:15PM
Re: T-Junctions re-visited Roland Melkert236March 15, 2013 11:29AM
Re: T-Junctions re-visited Travis Cobbs204March 15, 2013 12:27PM
Re: T-Junctions re-visited Ben Supnik209March 15, 2013 05:08PM
Re: T-Junctions re-visited Travis Cobbs203March 16, 2013 11:29PM
Re: T-Junctions re-visited Ben Supnik175March 17, 2013 08:58AM
Re: T-Junctions re-visited Roland Melkert177March 17, 2013 12:35PM
Re: T-Junctions re-visited Travis Cobbs198March 18, 2013 12:28PM
Re: T-Junctions re-visited Travis Cobbs211March 18, 2013 12:32PM
Re: T-Junctions re-visited Roland Melkert200March 18, 2013 05:00PM
Re: T-Junctions re-visited Travis Cobbs232March 18, 2013 11:05PM
Re: T-Junctions re-visited Roland Melkert241March 19, 2013 11:38AM
Re: T-Junctions re-visited Sergio Reano227March 26, 2013 02:46PM
Re: T-Junctions re-visited Roland Melkert192March 27, 2013 11:19AM
Re: T-Junctions re-visited Sergio Reano235March 27, 2013 01:48PM



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