[FieldTrip] Problem in ft_timelockstatistics() phase

Irina Simanova irina.simanova at mpi.nl
Thu May 3 16:43:08 CEST 2012

Hi Sander,

The multivariate analysis module is now being re-structured, so that it will
eventually become a stand-alone toolbox - Donders Machine Learning Toolbox,
DMLT. Your error is caused by a conflict between the old and the new
versions of the functions. You should just change the way you specify the
mva method: cfg.mva = {dml.standardizer dml.svm} (check the reference to
It should work then.


-----Original Message-----
From: fieldtrip-bounces at donders.ru.nl
[mailto:fieldtrip-bounces at donders.ru.nl] On Behalf Of Sander Maijers
Sent: Saturday, April 28, 2012 4:01 PM
To: fieldtrip at donders.ru.nl
Subject: [FieldTrip] Problem in ft_timelockstatistics() phase


I am trying to rework a small FieldTrip experiment I did last year
(reproduction of larger experiment done by Irina Simanova).

Calling ft_timelockstatistics() on two ERP data partitions results in an
error: "Undefined function 'fieldnames' for input arguments of type 'cell'."
I'm running FieldTrip under MATLAB R2011b 64-bit on Linux.

I see a possible cause of the problem, in that these data we pre-analysed
with ft_timelockanalysis() a year ago, or longer. I read them from parts of
the data set I was supplied with. Maybe there have been breaking changes to
this function in the meantime? The cfg struct that I pass as parameter seems
in line with the current documentation, though.


>> main()

data_set_location =

/media/SAMSUNG/0,data_set/EEG/0 MATLAB

output_dir =


Data set part file: timelock10_lp
Data set part file: timelock11_lp

[class 1, size = 220]: participant timelock10_lp on condition avg_anm_aud_lp
[class 2, size = 224]: participant timelock10_lp on condition avg_tls_aud_lp
     method: 'crossvalidate'
    latency: [0 0.7000]
    channel: {1x60 cell}
     nfolds: 5
        mva: {2x1 cell}
     design: [444x1 double]

        avg: [62x501 double]
        var: [62x501 double]
    fsample: 500
       time: [1x501 double]
        dof: [62x501 double]
      label: {62x1 cell}
      trial: [220x62x501 double]
     dimord: 'rpt_chan_time'
        cfg: [1x1 struct]

        avg: [62x501 double]
        var: [62x501 double]
    fsample: 500
       time: [1x501 double]
        dof: [62x501 double]
      label: {62x1 cell}
      trial: [224x62x501 double]
     dimord: 'rpt_chan_time'
        cfg: [1x1 struct]

selected 60 channels
selected 351 time bins
selected 1 frequency bins
using "ft_statistics_crossvalidate" for the statistical testing fixing
random number generator for reproducibility creating sample indices using
5-fold cross-validation validating fold 1 of 5 for 1 datasets validating
fold 2 of 5 for 1 datasets validating fold 3 of 5 for 1 datasets validating
fold 4 of 5 for 1 datasets validating fold 5 of 5 for 1 datasets Undefined
function 'fieldnames' for input arguments of type 'cell'.

Error in ft_statistics_crossvalidate (line 84) fn =

Error in statistics_wrapper (line 298)
    [stat] = statmethod(cfg, dat, design);

Error in ft_timelockstatistics (line 110) [stat, cfg] =
statistics_wrapper(cfg, varargin{:});

Error in main/modeling (line 203)
        stat = ft_timelockstatistics(cfg, class_1_datastruct,

Error in main/statistics (line 225)
            stat = modeling(data_set, method, obj_class_1_and_2);

Error in main/ERP_experiment (line 374)
            stats = statistics(data_set, contrasts, method);

Error in main (line 401)
    stats_x = ERP_experiment(data_set_location, 'RR', output_dir)

Any suggestions would be welcom!

Kind regards,
Sander Maijers
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fieldtrip at donders.ru.nl

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