[Simnibs-discuss] matsimnibs matrix and angles

[Kristoffer Madsen]

Just to elaborate a bit on Fangs answer when using an affine transformation
no particular order of transformations has to be specified. However, if you
require it to be represented as such you can decompose into any order you
like (there is a solution for any order - but it will be different for each
and unfortunately you have to solve a non-linear system). See for example
https://en.wikipedia.org/wiki/Transformation_matrix.
For solving for one particular order you can see for example:
https://github.com/neurodebian/spm12/blob/master/spm_imatrix.m (Matlab code
unfortunately).

Best,
Kristoffer

On Fri, 3 Sept 2021 at 11:43, Giacomo Bertazzoli <
giacomo.bertazzoli at unitn.it> wrote:

> Dear all,
> We would like to know how the output *affine transformation matrix*
> (matsimnibs) is obtained when simulating the efield or when doing the coil
> optimization. In particular we do not understand if that matrix is the
> result of multiple rotations and in the case in which order they occur (we
> supposed z-x-y). We need this information because we are trying to assess
> the difference (in angle) between two coil positions.
> All the very best,
>
> Giacomo
>
> --
> Giacomo Bertazzoli, PhD Candidate
> Cognition Neurostimulation & Connectivity Lab - CIMeC
> University of Trento, Corso Bettini 31, 38068 Rovereto (TN) Italy
> Email: giacomo.bertazzoli at unitn.it
> https://webapps.unitn.it/du/en/Persona/PER0194098
> https://www.linkedin.com/in/giacomo-bertazzoli-8737b160/
> <https://www.linkedin.com/in/giacomo-bertazzoli-8737b160/>
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