[Mne_analysis] error when initiating a raw object

[Dykstra, Andrew]

Dear MNE community,

I am experiencing an error that I don't understand when trying to create 
a raw object in Python.  The traceback is below, and I only get this 
with the raw files from one subject.  I initially thought that it could 
be due to the abnormally large file sizes of this subject's raw data 
(~700 Mb), but I have one other subject whose raw data were comparable 
and I can create raw objects from those data without issue.

Has anyone experienced this?

Cheers,
Andy

error                                     Traceback (most recent call last)
/home/andrew/Experiments/Awareness_wo_Attention/<ipython-input-8-5fbcd28d6772> 
in <module>()
----> 1 
runfile(r'/home/andrew/Experiments/Awareness_wo_Attention/py_tmp_check_dataset_channels.py', 
wdir=r'/home/andrew/Experiments/Awareness_wo_Attention')

/usr/local/lib/python2.7/dist-packages/spyderlib/widgets/externalshell/sitecustomize.pyc 
in runfile(filename, args, wdir, namespace)
     485             pass
     486         os.chdir(wdir)
--> 487     execfile(filename, namespace)
     488     sys.argv = ['']
     489     namespace.pop('__file__')

/home/andrew/Experiments/Awareness_wo_Attention/py_tmp_check_dataset_channels.py 
in <module>()
      48     for block in range(2):
      49         fname.append(data_path + '/' + subject + '/meg/' + 
subject + '_block' + str(block+1) + '_cleaned_raw.fif')
---> 50         raw.append(mne.fiff.Raw(fname[block]))
      51         chan.append(raw[block].ch_names)
      52     chan.append([x for x in chan[0] if x not in set(chan[1])])

/usr/local/lib/python2.7/dist-packages/mne-0.6.git-py2.7.egg/mne/utils.pyc 
in dec(*args, **kwargs)
     263             return ret
     264         else:
--> 265             return function(*args, **kwargs)
     266
     267     # set __wrapped__ attribute so ?? in IPython gets the right 
source


/usr/local/lib/python2.7/dist-packages/mne-0.6.git-py2.7.egg/mne/fiff/raw.pyc 
in __init__(self, fnames, allow_maxshield, preload, verbose, proj_active)
      83
      84         raws = [self._read_raw_file(fname, allow_maxshield, 
preload)
---> 85                 for fname in fnames]
      86
      87         _check_raw_compatibility(raws)

/usr/local/lib/python2.7/dist-packages/mne-0.6.git-py2.7.egg/mne/utils.pyc 
in dec(*args, **kwargs)
     263             return ret
     264         else:
--> 265             return function(*args, **kwargs)
     266
     267     # set __wrapped__ attribute so ?? in IPython gets the right 
source


/usr/local/lib/python2.7/dist-packages/mne-0.6.git-py2.7.egg/mne/fiff/raw.pyc 
in _read_raw_file(self, fname, allow_maxshield, preload, verbose)
     137         ext = os.path.splitext(fname)[1].lower()
     138         whole_file = preload if '.gz' in ext else False
--> 139         fid, tree, _ = fiff_open(fname, preload=whole_file)
     140
     141         #   Read the measurement info


/usr/local/lib/python2.7/dist-packages/mne-0.6.git-py2.7.egg/mne/utils.pyc 
in dec(*args, **kwargs)
     263             return ret
     264         else:
--> 265             return function(*args, **kwargs)
     266
     267     # set __wrapped__ attribute so ?? in IPython gets the right 
source


/usr/local/lib/python2.7/dist-packages/mne-0.6.git-py2.7.egg/mne/fiff/open.pyc 
in fiff_open(fname, preload, verbose)
      83         while tag.next >= 0:
      84             pos = fid.tell()
---> 85             tag = read_tag_info(fid)
      86             tag.pos = pos
      87             directory.append(tag)

/usr/local/lib/python2.7/dist-packages/mne-0.6.git-py2.7.egg/mne/fiff/tag.pyc 
in read_tag_info(fid)
      67     """
      68     s = fid.read(4 * 4)
---> 69     tag = Tag(*struct.unpack(">iiii", s))
      70     if tag.next == 0:
      71         fid.seek(tag.size, 1)

error: unpack requires a string argument of length 16

-- 
Andrew R. Dykstra, PhD
Auditory Cognition Lab
Neurologie und Poliklinik
Universitätsklinikum Heidelberg
Im Neuenheimer Feld 400
69120 Heidelberg

"How small the cosmos.  How paltry and puny compared to human consciousness . . . to a single individual recollection." - Vladimir Nabokov