Hello guys,

x, not A, is a rotational matrix, but you got the idea right. Your comment

made me notice that I have a problem with my destination reference system,

it is not orthogonal. Your solution probably works, using the tools

Christian pointed out (thanks Christian, I completely forgot about that part

of the tutorial!). So once I get my data fixed, I guess Iâ€™ll be able to use

the orthogonal matrix simplification you described to get the desired

result.

Thanks guys!

Jean-Olivier

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf

Of AnyBody Support

Sent: 7 fÃ©vrier 2007 03:06

To: anyscript@yahoogroups.com

Subject: Re: [anyscript] Right matrix divide / Inverse matrix

Hello Jean-Olivier and Christian,

I send this email yesterday - unfortunately from a wrong account, so it was

not accepted by the group’s mailserver. Christian answered in the meantime,

but I think you should have my answer too.

Here comes the text from yesterday

x=A/b, AnyFunRDivide, and AnyFunInvMat - it is all good ideas. I guess

something like this will come in time, especially if a lot of you out there

demand for it;-)

In general, it has never been the plan that AnyScript should be a Matlab

clone, but we will try to follow demands from the users, and Matlab

certainly sets a standard. However the functions you mention are not yet on

the wish-list for the next version, so I cannot say when we will manage -

sorry.

When you speak of reference axis, isn’t that right-hand coordinate reference

system, and the A matrix is a 3 by 3 rotational transformation matrix? It

sounds like it in your description.

If so the matrices are orthogonal, which implies that inv(A) = A^T (or A’ in

Matlab/AnyScript syntax).

You can easily test this of course by computing A’*A.

I hope I understood you correctly about A, because then you should be able

to deal with your case in current AnyScript.

Best regards,

Michael

From: <mailto:anyscript%40yahoogroups.com> anyscript@yahoogroups.com

[mailto: <mailto:anyscript%40yahoogroups.com> anyscript@yahoogroups.com] On

Behalf

Of Jean-Olivier Racine

Sent: Tuesday, February 06, 2007 16:20 PM

To: <mailto:anyscript%40yahoogroups.com> anyscript@yahoogroups.com

Subject: [anyscript] Right matrix divide / Inverse matrix

Good day,

As I am working on my model, I need to include bony landmarks. The reference

book I use uses a different axis for the segments (Paul Allard, 1995, in

this case). I therefore need to transform the bony landmarks coordinates

from their system to anybody’s. I can do all transformation by hand (i.e.

using matlab) and hardcode this information in the model, but I really don’t

like this idea because it means that the model is hard to maintain/modify. I

would rather calculate that transformation directly in the model, by

incorporating the reference axis from my source (A) and the reference axis

from the repository (b), and then use the right matrix division (Ax=b ->

x=A/b) to transform the data directly. I could therefore include, in the

model, the raw data from the book, and then transform it within anybody,

making the model a lot easier to maintain and more general.

In other words, I’d like to be able to calculate, within anybody, the

transformation matrix I would include in AnyFunTransform3DLin. For this, I

would need either a “AnyFunRDivide” or “AnyFunInvMat”, since x=A/b can

generally be calculated by x=A*Inv(b). Do any of those functions exist and I

missed it? Or this can’t be done? If it can’t be done, can’t it be added? Is

there another way to do this?

Thank you all!

Jean-Olivier

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