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Calculator Community => TI Calculators => TI-BASIC => Topic started by: Radical Pi on December 24, 2007, 11:25:00 am

Title: Rotation of a 3x3 matrix
Post by: Radical Pi on December 24, 2007, 11:25:00 am

So, I need to be able to do this for a certain *project* I'm working on. I didn't want to have to resort to a For() loop and manually store all coordinates into a temporary second matrix before overwriting the first one.
Is there any magical identity matrix that can do this? Or will I have to do it the boring way?

Just for clarification, I want:
c1-->

CODE

ec1[A B C] [D E F] [G H I]c2

ec2
to become:
c1

-->

CODE

ec1[G D A] [H E B] [I F C] or [C F I] [B E H] [A D G]c2

ec2

I'm doubting more and more that there's an efficient way of doing that, but if there is I can't seem to find it myself :P

Title: Rotation of a 3x3 matrix
Post by: vuurrobin on December 24, 2007, 12:17:00 pm

I think that rowswap([A],1,3)t would do the trick. the t is that superscript t for transpose

Title: Rotation of a 3x3 matrix
Post by: Radical Pi on December 24, 2007, 12:31:00 pm

That works perfectly :D
Thanks, I'll have to remember to mention you in the credits.

Title: Rotation of a 3x3 matrix
Post by: burr on December 24, 2007, 09:06:00 pm

If you need some help remembering the matrix commands, we have a page for that on TI|BD: http://tibasicdev.wikidot.com/matrices.