Wikipedia:Articles for deletion/Generalized quaternion interpolation

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The following discussion is an archived debate of the proposed deletion of the article below. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.

The result was delete. Cab be userfied on request for improvement. Sandstein 08:22, 29 April 2015 (UTC)[reply]

Generalized quaternion interpolation

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Outwith my area of expertise, but I couldn't establish its notability. Neither has anyone else in the 7 years it has been tagged for notability; hopefully at AfD we can get it resolved. Boleyn (talk) 16:57, 13 April 2015 (UTC)[reply]

Note: This debate has been included in the list of Science-related deletion discussions. • Gene93k (talk) 18:35, 14 April 2015 (UTC)[reply]

Note: This debate has been included in the list of Computing-related deletion discussions. • Gene93k (talk) 18:36, 14 April 2015 (UTC)[reply]

delete. I've read it through twice but can’t make sense of it. There are ways to do what it’s trying to do, interpolate between more than two quaternions, but it doesn’t seem to get close to any of them, or anything that I can make sense of.--JohnBlackburne^words_deeds 01:47, 20 April 2015 (UTC)[reply]

Relisted to generate a more thorough discussion so a clearer consensus may be reached.
Please add new comments below this notice. Thanks, North America¹⁰⁰⁰ 00:34, 21 April 2015 (UTC)[reply]

Delete I found the (single) reference online: [1]. The whole thing looks borderline WP:NOTESSAY and complete gibberish. I first tried to understand what this article is about without the reference with my smattering of elemental mathematics, and frankly the most basic things are not correctly explained. Some basic and probably incorrect summary of the reference follows with as little jargon as possible:

The main problem is to measure a 3d rotation. We have multiple measurements with uncertainty attached to each of them and we want to take a guess of what the real value is. Notice this "value" is a three-parameter thing, for instance axis of rotation (2 degrees of freedom) and angle (1 DoF), so it can be represented by a unit vector of the quaternion space (if you forget about compositions of rotations, that's equivalent to a 3-sphere).

The "naive" way to look at the problem is to use some weighted average of the measurements (it is already not that easy if measurements have inconsistent error bars). But the thing is, that average is not easy to define, for instance the average of a set of unit vectors is not a unit vector, so you cannot find a straightforward geometrical definition for "average" here, because there are additional constraints on our objects (they must fit on a sphere). The article then proceeds to describe an algorithm that supposedly finds a good solution to the problem for a reason I do not quite see.

Even if the article was rewritten into a clear, concise and correct summary of that reference, I am still not seeing how this could possibly be considered notable. Tigraan (talk) 15:35, 22 April 2015 (UTC)[reply]

Delete—I think Tigraan's analysis is more than generous. I'm not finding any WP:RS where the concept is discussed under this name. Not sufficient notability for an article. Lesser Cartographies (talk) 22:33, 26 April 2015 (UTC)[reply]
Comment. The goal is to find a unit quaternion m such that preimages of the points $p_{i}$ under the exponential map sum to zero in the tangent space to the unit sphere at m (with weights $w_{i}$ ). The point(s) m solving this problem is/are the same as the Karcher mean on the three-sphere. So the subject of the article is not nonsense, in my opinion. Whether it has enough sense to keep, I defer to others' judgement, although I lean slightly towards "keep and improve" myself. Sławomir Biały (talk) 11:48, 27 April 2015 (UTC)[reply]

@Slawekb: Any leads on where this has been discussed in the literature? I've happy to give quite a bit of leeway on math articles, but without any sources I'm concerned about the WP:OR aspect. Lesser Cartographies (talk) 06:57, 28 April 2015 (UTC)[reply]

I was able to find this: http://labvis.isr.uc.pt/robomat/papers/T1_2.pdf, which does something similar but without the weights. Sławomir Biały (talk) 11:06, 28 April 2015 (UTC)[reply]

@Slawekb: If you want to try your hand at incorporating this cite then that would be sufficient for me to change my !vote. Lesser Cartographies (talk) 06:52, 29 April 2015 (UTC)[reply]

The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.