Hi again PRteam, I found useful to have a grouping variable in my feature matrix to separate feature vectors extracted from different experiments, in my case different pacients. The best way I found to implement this feature was with the USER field, and the update of this variable was done in my application, but I suppose that could be implemented like a dataset property, and some methods like SUBREF, etc could update this variable automatically. I used this variable to perform cross-validation in a leave-one-pacient-out fashion, and different training-testing aggrupations. Maybe there is a best way to do this with the existing features ... what do you think?

Mariano.

Dear Mariano,

yes, this facility is available. PRTools provides the low-level identifier field (ident) where you can store additional per-sample information. Check out
the getident/setident functions where you can define your own fields.
PRSD Studio builds some higher-level functionality using identifiers. You can, for example, define your ‘patient’ property in a dataset and then quickly retrieve indices of dataset samples that correspnd to a set of patients (using setprop and findprop functions resp.) See the example in the documentation http://prsysdesign.net/files/doc/PRSDmanual.html#[[Preparing the data]]
PRSD Studio supports cross-validation over a user-defined property. It will be, however, available in the public evaluation version only after 1.1.3 gets out in the coming days.

Pavel

Thanks again ! Mariano.