def test_memmap():
fname='ec_rest_before_tsss_mc_rsl.fif'
raw = Raw(fname, preload=False)
raw.preload_data() # data becomes numpy.float64
data_shape = raw._data.shape
tmpdir = mkdtemp(dir='/Users/cjb/tmp')
mmap_fname = opj(tmpdir, 'raw_data.dat')
fp = np.memmap(mmap_fname, dtype='float64', mode='w+',
shape=data_shape)
print('Contents of raw._data:')
print(raw._data[0][:10])
print('Contents of memmap:')
print(fp[0][:10])
fp[:] = raw._data[:]
print('Contents of memmap after assignment:')
print(fp[0][:10])
# delete numpy array and the memmap writer
del raw._data
del fp
raw._data = np.memmap(mmap_fname, dtype='float64', mode='r+',
shape=data_shape)
print('Contents of raw._data after loading from memmap:')
print(raw._data[0][:10])
raw.filter(None,40)
print('Contents of raw._data after filtering:')
print(raw._data[0][:10])
def test_preload_memmap():
tmpdir = mkdtemp(dir="/Users/cjb/tmp")
mmap_fname = opj(tmpdir, "raw_data.dat")
# fname='ec_rest_before_tsss_mc_rsl.fif'
data_path = sample.data_path(download=False)
fname = data_path + "/MEG/sample/sample_audvis_raw.fif"
raw = Raw(fname, preload=False)
# """This function actually preloads the data"""
# data_buffer = mmap_fname
# raw._data = raw._read_segment(data_buffer=data_buffer)[0]
# assert len(raw._data) == raw.info['nchan']
# raw.preload = True
# raw.close()
raw.preload_data(data_buffer=mmap_fname)
data_shape = raw._data.shape
print("Contents of raw._data after reading from fif:")
print(type(raw._data))
print(raw._data[100][:5])
del raw._data
raw._data = np.memmap(mmap_fname, dtype="float64", mode="c", shape=data_shape)
print("Contents of raw._data after RE-loading:")
print(type(raw._data))
print(raw._data[100][:5])
raw.filter(None, 40)
print("Contents of raw._data after filtering:")
print(type(raw._data))
print(raw._data[100][:5])
# PROBLEM: Now the filtered data are IN MEMORY, but as a memmap
# What if I'd like to continue from here using it as an ndarray?
del raw._data
rmtree(tmpdir, ignore_errors=True)
def filter(l_freq, h_freq, picks=None, filter_length='10s',
l_trans_bandwidth=0.5, h_trans_bandwidth=0.5, n_jobs=1,
method='fft', iir_params=None, verbose=None):
"""Filter a subset of channels.
Applies a zero-phase low-pass, high-pass, band-pass, or band-stop
filter to the channels selected by "picks". The data of the Raw
object is modified inplace.
The Raw object has to be constructed using preload=True (or string).
l_freq and h_freq are the frequencies below which and above which,
respectively, to filter out of the data. Thus the uses are:
* ``l_freq < h_freq``: band-pass filter
* ``l_freq > h_freq``: band-stop filter
* ``l_freq is not None and h_freq is None``: high-pass filter
* ``l_freq is None and h_freq is not None``: low-pass filter
If n_jobs > 1, more memory is required as "len(picks) * n_times"
additional time points need to be temporarily stored in memory.
raw.info['lowpass'] and raw.info['highpass'] are only updated
with picks=None.
Parameters
----------
l_freq : float | None
Low cut-off frequency in Hz. If None the data are only low-passed.
h_freq : float | None
High cut-off frequency in Hz. If None the data are only
high-passed.
picks : array-like of int | None
Indices of channels to filter. If None only the data (MEG/EEG)
channels will be filtered.
filter_length : str (Default: '10s') | int | None
Length of the filter to use. If None or "len(x) < filter_length",
the filter length used is len(x). Otherwise, if int, overlap-add
filtering with a filter of the specified length in samples) is
used (faster for long signals). If str, a human-readable time in
units of "s" or "ms" (e.g., "10s" or "5500ms") will be converted
to the shortest power-of-two length at least that duration.
Not used for 'iir' filters.
l_trans_bandwidth : float
Width of the transition band at the low cut-off frequency in Hz
(high pass or cutoff 1 in bandpass). Not used if 'order' is
specified in iir_params.
h_trans_bandwidth : float
Width of the transition band at the high cut-off frequency in Hz
(low pass or cutoff 2 in bandpass). Not used if 'order' is
specified in iir_params.
n_jobs : int | str
Number of jobs to run in parallel. Can be 'cuda' if scikits.cuda
is installed properly, CUDA is initialized, and method='fft'.
method : str
'fft' will use overlap-add FIR filtering, 'iir' will use IIR
forward-backward filtering (via filtfilt).
iir_params : dict | None
Dictionary of parameters to use for IIR filtering.
See mne.filter.construct_iir_filter for details. If iir_params
is None and method="iir", 4th order Butterworth will be used.
verbose : bool, str, int, or None
If not None, override default verbose level (see mne.verbose).
Defaults to raw.verbose.
See Also
--------
mne.Epochs.savgol_filter
"""
fname='ec_rest_before_tsss_mc_rsl.fif'
raw = Raw(fname, preload=False)
raw.preload_data() # data becomes numpy.float64
if verbose is None:
verbose = raw.verbose
fs = float(raw.info['sfreq'])
if l_freq == 0:
l_freq = None
if h_freq is not None and h_freq > (fs / 2.):
h_freq = None
if l_freq is not None and not isinstance(l_freq, float):
l_freq = float(l_freq)
if h_freq is not None and not isinstance(h_freq, float):
h_freq = float(h_freq)
if not raw.preload:
raise RuntimeError('Raw data needs to be preloaded to filter. Use '
'preload=True (or string) in the constructor.')
if picks is None:
if 'ICA ' in ','.join(raw.ch_names):
pick_parameters = dict(misc=True, ref_meg=False)
else:
pick_parameters = dict(meg=True, eeg=True, ref_meg=False)
picks = pick_types(raw.info, exclude=[], **pick_parameters)
# let's be safe.
if len(picks) < 1:
raise RuntimeError('Could not find any valid channels for '
'your Raw object. Please contact the '
'MNE-Python developers.')
# update info if filter is applied to all data channels,
# and it's not a band-stop filter
if h_freq is not None:
if (l_freq is None or l_freq < h_freq) and \
(raw.info["lowpass"] is None or
h_freq < raw.info['lowpass']):
raw.info['lowpass'] = h_freq
if l_freq is not None:
if (h_freq is None or l_freq < h_freq) and \
(raw.info["highpass"] is None or
l_freq > raw.info['highpass']):
raw.info['highpass'] = l_freq
if l_freq is None and h_freq is not None:
low_pass_filter(raw._data, fs, h_freq,
filter_length=filter_length,
trans_bandwidth=h_trans_bandwidth, method=method,
iir_params=iir_params, picks=picks, n_jobs=n_jobs,
copy=False)
if l_freq is not None and h_freq is None:
high_pass_filter(raw._data, fs, l_freq,
filter_length=filter_length,
trans_bandwidth=l_trans_bandwidth, method=method,
iir_params=iir_params, picks=picks, n_jobs=n_jobs,
copy=False)
if l_freq is not None and h_freq is not None:
if l_freq < h_freq:
raw._data = band_pass_filter(
raw._data, fs, l_freq, h_freq,
filter_length=filter_length,
l_trans_bandwidth=l_trans_bandwidth,
h_trans_bandwidth=h_trans_bandwidth,
method=method, iir_params=iir_params, picks=picks,
n_jobs=n_jobs, copy=False)
else:
raw._data = band_stop_filter(
raw._data, fs, h_freq, l_freq,
filter_length=filter_length,
l_trans_bandwidth=h_trans_bandwidth,
h_trans_bandwidth=l_trans_bandwidth, method=method,
iir_params=iir_params, picks=picks, n_jobs=n_jobs,
copy=False)
