Hi,
On 16 May 2007, at 16:25, Cinly Ooi wrote:
>> I'm not sure what you mean by "orthogonalized contrast" ?
>
> In GLM Setup (window)-> Higher order / non time series design ->
> General Linear Model (Window)
>
> Increase the number of EV and a button named "Setup Orthogonalization"
> will appear, click on the button will give you push buttons for each
> EV. See attached.
>
> I noticed that if you click on either of the push button, the value in
> design.mat will be orthogonalized. That's what I meant by
> "orhogonalized contrast" (probably the wrong words used)
Right - so we need to be clear - it's the EVs that are getting
changed when you orthogonalize, not the contrasts.
> Is it possible to generate the orthogonalized version of the
> design.mat file if I supply a non-orthogonalized one?
You would only be able to get FEAT to do this for you if you setup a
complete design.fsf file and then passed this through feat_model.cc
Otherwise you will need to implement the orthogonalisation which in
FEAT is part of feat_model.cc - the maths is as simple as you might
assume though!
Cheers, Steve.
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Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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