def rm_baseline(ndvar, tstart=None, tend=0, name='{name}'):
"""
returns an ndvar object with baseline correction applied.
ndvar : ndvar
the source data
tstart : scalar | None
the beginning of the baseline period (None -> the start of the epoch)
tend : scalar | None
the end of the baseline period (None -> the end of the epoch)
name : str
name for the new ndvar
"""
subdata = ndvar.subdata(time=(tstart, tend))
baseline = subdata.summary('time')
t_ax = subdata.get_axis('time')
index = (slice(None),) * t_ax + (None,)
bl_data = baseline.x[index]
dims = ndvar.dims
data = ndvar.x - bl_data
name = name.format(name=ndvar.name)
return _data.ndvar(data, dims=dims, properties=ndvar.properties, name=name)
def get_load(self, i):
time = self.source.get_dim('time')
dims = ('case', time,)
shape = (len(self.source), len(time))
data = self._proj[:, i].reshape(shape)
name = 'comp_%i_load' % i
ndvar = _data.ndvar(data, dims=dims, name=name)
return ndvar
def rm_pca(ds, rm=[], source='MEG', target='MEG'):
"""
Perform PCA and remove certain components. Use gui.pca to find components
initially. Algorithm from the gui!
"""
if not rm:
raise ValueError("No components selected")
if isinstance(source, basestring):
source = ds[source]
rm = sorted(rm)
n_comp = max(rm) + 1
# do the pca
pca = _mdp.nodes.PCANode(output_dim=n_comp)
for epoch in source.data:
pca.train(epoch)
pca.stop_training()
# remove the components
n_epochs, n_t, n_sensors = source.data.shape
data = source.data.copy() # output data
# take serialized data views for working with the PCANode
new_data = data.view()
old_data = source.data.view()
# reshape the views
new_data.shape = (n_epochs * n_t, n_sensors)
old_data.shape = (n_epochs * n_t, n_sensors)
# project the components and remove
proj = pca.execute(old_data)
for i in xrange(proj.shape[1]):
if i not in rm:
proj[:,i] = 0
rm_comp_data = pca.inverse(proj)
new_data -= rm_comp_data
# create the output new ndvar
dims = source.dims
properties = source.properties
ds[target] = _data.ndvar(dims, data, properties, name=target)
def add_fiff_to_events(path, dataset, i_start='i_start',
tstart=-.2, tstop=.6, properties=None,
name="MEG", sensorsname='fiff-sensors'):
"""
Adds MEG data form a new file to a dataset containing events.
"""
events = np.empty((dataset.N, 3), dtype=np.uint32)
events[:,0] = dataset[i_start].x
events[:,1] = 0
events[:,2] = 1
raw = mne.fiff.Raw(path)
# parse sensor net
sensor_list = []
for ch in raw.info['chs']:
ch_name = ch['ch_name']
if ch_name.startswith('MEG'):
x, y, z = ch['loc'][:3]
sensor_list.append([x, y, z, ch_name])
sensor_net = sensors.sensor_net(sensor_list, name=sensorsname)
picks = mne.fiff.pick_types(raw.info, meg=True, eeg=False, stim=False,
eog=False, include=[], exclude=[])
# read the data
epochs = mne.Epochs(raw, events, 1, tstart, tstop, picks=picks)
data = np.array([e.T for e in epochs.get_data()])
props = {'samplingrate': epochs.info['sfreq'][0]}
props.update(_default_fiff_properties)
if properties:
props.update(properties)
T = epochs.times
timevar = _data.var(T, 'time')
dims = (timevar, sensor_net)
dataset.add(_data.ndvar(dims, data, properties=props, name=name))
dataset.default_DV = name
def subtract(self, components, baseline=(None, 0), name='{name}'):
"""
returns a copy of the source ndvar with the principal
components specified in ``components`` removed.
Arguments:
components : list of ints
list of components to remove
baseline : True | False | (int|None, int|None)
Baseline correction after subtracting the components. True -> use the
settings stored in the ndvar.properties; False -> do not apply any
baseline correction; a new baseline can be specified with a tuple of
two time values or None (use all values until the end of the epoch).
"""
data = self._source_data
proj = self._proj
# flatten retained components
for i in xrange(proj.shape[1]):
if i not in components:
proj[:, i] = 0
# remove the components
rm_comp_data = self.node.inverse(proj)
new_data = data - rm_comp_data.reshape(data.shape)
new_data = new_data.astype(self._source_dtype)
# create the output new ndvar
dims = ('case',) + self.source.get_dims(('time', 'sensor'))
properties = self.source.properties
name = name.format(name=self.source.name)
out = _data.ndvar(new_data, dims=dims, properties=properties, name=name)
if baseline:
tstart, tend = baseline
out = rm_baseline(out, tstart, tend)
return out
def get_component(self, i):
dims = self.source.get_dims(('sensor',))
data = self.node.v.T[i, ]
name = 'comp_%i' % i
ndvar = _data.ndvar(data, dims, name=name)
return ndvar
def fiff_epochs(dataset, i_start='i_start',
tstart=-.2, tstop=.6, baseline=(None, 0),
properties=None, name="MEG", sensorsname='fiff-sensors'):
"""
Uses the events in ``dataset[i_start]`` to extract epochs from the raw
file
i_start : str
name of the variable containing the index of the events to be
imported
"""
events = np.empty((dataset.N, 3), dtype=np.int32)
events[:,0] = dataset[i_start].x
events[:,1] = 0
events[:,2] = 1
source_path = dataset.info['source']
raw = mne.fiff.Raw(source_path)
# parse sensor net
sensor_list = []
for ch in raw.info['chs']:
ch_name = ch['ch_name']
if ch_name.startswith('MEG'):
x, y, z = ch['loc'][:3]
sensor_list.append([x, y, z, ch_name])
sensor_net = sensors.sensor_net(sensor_list, name=sensorsname)
picks = mne.fiff.pick_types(raw.info, meg=True, eeg=False, stim=False,
eog=False, include=[], exclude=[])
epochs = mne.Epochs(raw, events, 1, tstart, tstop, picks=picks,
baseline=baseline)
# determine data container properties
epoch_shape = (len(picks), len(epochs.times))
data_shape = (len(events), len(epochs.times), len(picks))
# mne.fiff.raw.read_raw_segment uses float32
data = np.empty(data_shape, dtype='float32')
# read the data
for i, epoch in enumerate(epochs):
if epoch.shape == epoch_shape:
data[i] = epoch.T
else:
msg = ("Epoch %i shape mismatch: does your epoch definition "
"result in an epoch that overlaps the end of your data "
"file?" % i)
raise IOError(msg)
# read data properties
props = {'samplingrate': epochs.info['sfreq'][0]}
props.update(_default_fiff_properties)
if properties:
props.update(properties)
T = epochs.times
timevar = _data.var(T, 'time')
dims = (timevar, sensor_net)
dataset.add(_data.ndvar(dims, data, properties=props, name=name))
dataset.default_DV = name
def fiff(raw, events, conditions, varname='condition', dataname='MEG',
tstart=-.2, tstop=.6, properties=None, name=None, c_colors={},
sensorsname='fiff-sensors'):
"""
Loads data directly when two files (raw and events) are provided
separately.
conditions : dict
ID->name dictionary of conditions that should be imported
event : str
path to the event file
properties : dict
set properties in addition to the defaults
raw : str
path to the raw file
varname : str
variable name that will contain the condition value
"""
if name is None:
name = os.path.basename(raw)
raw = mne.fiff.Raw(raw)
# parse sensor net
sensor_list = []
for ch in raw.info['chs']:
ch_name = ch['ch_name']
if ch_name.startswith('MEG'):
x, y, z = ch['loc'][:3]
sensor_list.append([x, y, z, ch_name])
sensor_net = sensors.sensor_net(sensor_list, name=sensorsname)
events = mne.read_events(events)
picks = mne.fiff.pick_types(raw.info, meg=True, eeg=False, stim=False,
eog=False, include=[], exclude=[])
data = []
c_x = []
# read the data
for ID in conditions:
epochs = mne.Epochs(raw, events, ID, tstart, tstop, picks=picks)
samplingrate = epochs.info['sfreq'][0]
# data
c_data = epochs.get_data() # n_ep, n_ch, n_t
for epoch in c_data:
data.append(epoch.T)
# data.append(c_data.T)
T = epochs.times
# conditions variable
n_ep = len(c_data)
c_x.extend([ID] * n_ep)
# construct the dataset
c_factor = _data.factor(c_x, name=varname, labels=conditions,
colors=c_colors, retain_label_codes=True)
props = {'samplingrate': samplingrate}
props.update(_default_fiff_properties)
if properties is not None:
props.update(properties)
data = np.array(data)
# data = np.concatenate(data, axis=0)
timevar = _data.var(T, 'time')
dims = (timevar, sensor_net)
Y = _data.ndvar(dims, data, properties=props, name=dataname)
dataset = _data.dataset(Y, c_factor, name=name, default_DV=dataname)
return dataset
