[VoxBo] Adding derivativesin GDW error

[Dongbo Hu]

Because of the way derivative is calculated, a covariate that has odd
number of time points is not supported for derivatives right now. I
thought of this problem a few years ago when writing that part of the
code. It turned out that you are the first user who got this problem. Let
me check the code on Monday and see how easy it may be to fix it.

Dongbo

On Fri, 23 Mar 2007, Rob Blumenfeld wrote:

>_Hey Voxbo group,
>_
>_  I am getting an error when I try to add derivatives to my GLM in the
>_G-Design Widget. After selecting the covariates of interest that I want to
>_add a derivative to, I click modify selection-->derivative(s) and then I
>_receive the message that the number of observations must be an even number.
>_Indeed, my study has an odd number of timepoints (1575). I get this message
>_regardless of whether I selected one covariate or multiple covariates. My
>_question is: Is this an error or there some reason why I can not add
>_derivatives into to a study that has an odd number of timepoints? Any help
>_would be greatly appreciated.
>_
>_Thanks for your time,
>_
>_-Rob
>_
>_
>_
>_Rob Blumenfeld
>_
>_Dynamic Memory Lab
>_
>_UC Davis Psychology & Center for Neuroscience
>_
>_
>_
>_
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>_