If you have added additional contrasts you can run them by using the ( hidden )--skipTo=n option in randomise, this will advance to the nth contrast ( counting any f-tests first ). e.g if you add contrast 21 to your design then adding
will run randomise only on the 21st contrast ( assuming there are no f-tests ). If you had 3 f-tests then the call would need to be
for the same result.
> Dear FSL-ers,
> I was wondering whether there is a way to quickly run some additional contrasts using randomise without rerunning the complete model again. In my case I am running a VBM analyses with more than 400 subjects and about 20 contrasts, so knowing how to "add" a few contrasts without running all the others again might save me a couple of days computational time.
> If I could simply calculate the non-parametric reverse contrast of existing contrasts (e.g. HC > PATIENTS based on an existing PATIENTS > HC contrast), that would also be fine already. I was used to standard parametric statistics before using randomise. With standard statistics one can simply use positive and negative z-scores, but this is obviously not going to work when using permutation-based testing given the directional testing and the resulting p-values.
> Thanks a lot for your help in advance.
> Best, Henk