On Wed, 12 Aug 2015, Roni Maimon wrote: > So the full design is I have 4 conditions in 8 runs. 5 blocks of each > condition in each run. > All runs have all the conditions but I'm interested only in two > classifications and the differences between these classifications. > The order of trials is different across runs. > Some recommend I only permute the labels within runs, is this what you're > referring to?
it depends on the meaning of "permute the labels": - completely randomly shuffle all the labels, e.g. ababab could become anything of aaabbb, ababab, aabbab, .. that is the default behavior of AttributePermutator -- strategy='simple' - or "reassign" the labels i.e. ababab can become only bababa or ababab in that run (since we have only two labels) that is the strategy='uattrs' in both of above cases, permutations should happen strictly within each chunk/run (that is a must) -- use limit='chunks' . But as you might have noted, complete permutation (strategy='simple') might not pin point deficient designs (i.e. ababab). And then the strategy='chunks' is when you take complete sequence of trials from one run and assign to another. If your trials lost original order when you e.g. extracted betas -- this strategy is not applicable. > Is there a quick way to do that in pyMVPA? see above ;) AttributePermutator is the one doing it 'quickly' ;) -- Yaroslav O. Halchenko, Ph.D. http://neuro.debian.net http://www.pymvpa.org http://www.fail2ban.org Research Scientist, Psychological and Brain Sciences Dept. Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755 Phone: +1 (603) 646-9834 Fax: +1 (603) 646-1419 WWW: http://www.linkedin.com/in/yarik _______________________________________________ Pkg-ExpPsy-PyMVPA mailing list Pkg-ExpPsy-PyMVPA@lists.alioth.debian.org http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/pkg-exppsy-pymvpa