[pymvpa] using Balancer()

[Edmund Chong]

Hi all,
Currently I have unbalanced samples in each run (unequal number of samples
per condition).

If I do leave-one-run-out classification, am I correct to use the following
partitioner in my classifier to ensure an equal number of samples per
condition, for each classification fold?

ChainNode([NFoldPartitioner(),Balancer(attr='targets',count=1,limit='partitions',apply_selection=True)],space='partitions'))


Also, what happens if in some runs, I have no trials for a certain
condition? I imagine that on folds where those runs are part of the "test
dataset", this would be problematic (nothing to test against)?  So are
those fold entirely excluded from the analysis if I use Balancer?

Thanks!
-Edmund
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