Back to the main page.

Bug 675 - ft_freqstatistics errors with single-dimension data (avgovertime/chan/freq='yes')

Reported 2011-05-17 21:31:00 +0200
Modified 2011-05-25 15:07:54 +0200
Product: FieldTrip
Component: core
Version: unspecified
Hardware: Macintosh
Operating System: Mac OS
Importance: P1 normal
Assigned to: Jan-Mathijs Schoffelen
Depends on:
See also:

Matt Mollison - 2011-05-17 21:31:19 +0200

I'm using fieldtrip-20110516 on MATLAB 2010b. I sometimes use fieldtrip's stats for simple within subject (paired sample) experiment t-tests (method='analytic', statistic='depsamplesT'). The recent changes to ft_freqstatistics has changed something regarding these simple analyses and now it crashes. They're simple analyses in that I average over time, channel, and frequency data such that each subject ends up being represented by a single value. Here's a chunk of example code using the data from the cluster_permutation_freq tutorial that errors in the same place that it does for my own scripts. Note that the error happens at the reshape command on line 305 because cfg.dim only contains a single number, and cfg.dim gets set on line 228. Maybe line 228 should use the "size" command instead of "siz"? cfg.dim = size(reduceddim); % ============================================== load GA_TFR_orig; cfg = []; = {'MEG'}; cfg.latency = [0.5 0.8]; cfg.frequency = [20 20]; cfg.avgovertime = 'yes'; cfg.avgoverchan = 'yes'; cfg.avgoverfreq = 'yes'; cfg.method = 'analytic'; cfg.statistic = 'depsamplesT'; cfg.computestat = 'yes'; cfg.computecritval = 'yes'; cfg.computeprob = 'yes'; cfg.tail = 0; % -1, 0, or 1, left, two-sided, or right cfg.alpha = 0.05; cfg.correctm = 'no'; subj = 10; design = zeros(2,2*subj); for i = 1:subj design(1,i) = i; end for i = 1:subj design(1,subj+i) = i; end design(2,1:subj) = 1; design(2,subj+1:2*subj) = 2; = design; cfg.uvar = 1; cfg.ivar = 2; [stat] = ft_freqstatistics(cfg, GA_TFRFIC, GA_TFRFC); % ============================================== Unrelated to this bug, would it also be possible to prevent so much writing to the command window (e.g., "selection powspctrm along dimension 2/averaging powspctrm over chan")? I don't know where that gets printed in fieldtrip, but it sure outputs a lot of text. Matt

Jan-Mathijs Schoffelen - 2011-05-17 21:38:26 +0200

Hi Matt, Sorry for this. My fault. Thanks for the detailed report. I'll look into it as soon as possible.

Jan-Mathijs Schoffelen - 2011-05-18 08:59:51 +0200

fixed it in line 228: cfg.dim = [size(reduceddim) 1];