[pymvpa] How to set the chunks with the independent samples?
zonglei.fsl at gmail.com
Thu May 26 11:35:37 UTC 2011
Thanks very much. If we set he chunks to a unique value per subject. Then
all chunk-wise preprocessing of the raw data (e.g. zscore) will be improper.
We thus need to preprocess the data out of the whole ChainMapper. Am I
On Thu, May 26, 2011 at 6:46 PM, Michael Hanke <michael.hanke at gmail.com>wrote:
> On Thu, May 26, 2011 at 02:31:21PM +0800, Zhen Zonglei wrote:
> > We want to train a classifier to decode the state of subject (Patient
> > vs. Normal) from a neuroimaging parameter map and evaluate the accuracy.
> > samples are independent and no clear group of the subjects exists. How
> > should we set the chunk in pymvpa?
> > Another similar question: If we try to predict a mental score from the
> > neuroimaging parameter map for each subject with regression analysis,
> > how should we set the chunks?
> Independent of what you want to do with the data, the chunks indicate
> mutually independent portions of data. If you suspect that there are no
> dependencies between you subjects, you should set the chunks to a unique
> value per subject. I.e.
> chunks = np.arange(len(dataset))
> Michael Hanke
> Pkg-ExpPsy-PyMVPA mailing list
> Pkg-ExpPsy-PyMVPA at lists.alioth.debian.org
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