Subject:
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Re: Inverse matrix?
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Newsgroups:
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lugnet.cad.ray, lugnet.cad
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Date:
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Sat, 7 Apr 2007 18:40:03 GMT
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Viewed:
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651 times
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In lugnet.cad.ray, James Reynolds wrote:
> Does anyone know how to generate an inverse matrix. By inverse I mean it will
> undo the rotation of the original matrix. I thought the inverse of
> <1,0,0,0,1,0,0,0,1,0,0,0> was <-1,0,0,0,-1,0,0,0,-1,0,0,0>. In other words,
> multiply every value by -1.
>
> I know POV-Ray 3.6 has an inverse matrix function but it doesn't work in 3.1,
> which is what I'm using.
The inverse of <1,0,0,0,1,0,0,0,1,0,0,0> is itself.
To compute the inverse of a general 3x3 matrix (essentially what you need to do)
is rather complicated. You could do it in a macro using Gaussian elimination
[1].
Tim
[1] http://en.wikipedia.org/wiki/Gaussian_elimination
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Message has 1 Reply:
 | | Re: Inverse matrix?
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| (...) Arg. I thought this was going to be easy. I liked this part of the wikipedia article: "In practice, inverting a matrix is rarely required. Most of the time, one is really after the solution of a particular system of linear equations." Hm. I (...) (18 years ago, 7-Apr-07, to lugnet.cad.ray, lugnet.cad)
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Message is in Reply To:
| | Inverse matrix?
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| Does anyone know how to generate an inverse matrix. By inverse I mean it will undo the rotation of the original matrix. I thought the inverse of <1,0,0,0,1,0,0,0,1,0,0,0> was <-1,0,0,0,-1,0,0,0,-1,0,0,0>. In other words, multiply every value by -1. (...) (18 years ago, 7-Apr-07, to lugnet.cad.ray, lugnet.cad)
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