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Re: matrix operation [message #74100 is a reply to message #74099]

Thu, 23 December 2010 07:50

pgrigis
Messages: 436
Registered: September 2007

Senior Member

For large values of N, the methods you mentioned are likely
to be slower then a simple addition/multiplication combo.

x'=a1*x+b1*y+c1*z+d1
y'=a2*x+b2*y+c2*z+d2
z'=a3*x+b3*y+c3*z+d3

Ciao,
Paolo

On Dec 23, 9:39 am, Gray <grayliketheco...@gmail.com> wrote:
> Hi all,
>
> I'm just getting really confused about how to do this properly. Can
> you all help?
>
> I have a list of x y coordinates, and I want to perform an affine
> transformation on them, so I have a 3xN array of (xi,yi,1) and a 3x3
> matrix for my transformation, and I want to end up with a 3xN array of
> (x'i,y'i,1). How can I transform all my coordinates at once? I know
> my tools are #, ##, transpose/reform, and matrix_multiply, but I seem
> to be chronically unable to sort this out. Thanks!
>
> --Gray

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[Message index]

		Re: matrix operation By: rogass on Tue, 28 December 2010 12:09
		Re: matrix operation By: Gray on Thu, 23 December 2010 08:08
		Re: matrix operation By: pgrigis on Thu, 23 December 2010 07:50

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