FiffEpochData

Namespace: FIFFLIB  ·  Library: FIFF Library

#include <fiff/fiff_epochs.h>

struct FIFFLIB::FiffEpochData

Fixed-length epoching result: the (nepoch × nchan × nsamples) data stack plus the matching FiffInfo.

Returned by the static epoch-cutting helpers of FiffEpochs. Mirrors the mne.EpochsArray construction return value in MNE-Python.

src/examples/ex_fiff_structure/main.cpp

QFile rawFile(rawPath);
FiffRawData raw(rawFile);
MatrixXd data;
MatrixXd times;
ok &= raw.read_raw_segment(data, times); // all 6007 samples
const double sfreq = raw.info.sfreq;
const QList<FiffEpochData> epochs = FiffEpochs::makeFixedLengthEpochs(data, sfreq, 2.0, 0.5); // 2 s, 0.5 s overlap
const FiffEvoked average = FiffEpochs::averageEpochs(epochs, sfreq);

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Example

• Full source: src/examples/ex_fiff_structure/main.cpp
• Build target: ex_fiff_structure (runs under CTest)
• Data: mne-cpp-test-data

Used in examples

ex_fiff_structure

FIFF library: fixed-length epochs, CTF compensation, the file directory and raw buffers, and handing.

src/examples/ex_fiff_structure/main.cpp, line 98

MatrixXd times;
ok &= raw.read_raw_segment(data, times); // all 6007 samples
const double sfreq = raw.info.sfreq;
const QList<FiffEpochData> epochs = FiffEpochs::makeFixedLengthEpochs(data, sfreq, 2.0, 0.5); // 2 s, 0.5 s overlap
const FiffEvoked average = FiffEpochs::averageEpochs(epochs, sfreq);
// mne.make_fixed_length_epochs(raw, duration=2, overlap=0.5): 13 epochs of 601 samples, 450 samples apart
ok &= expect(epochs.size() == 13 && epochs[0].data.cols() == 601 && std::lround((epochs[1].tmin - epochs[0].tmin) * sfreq) == 450 && average.nave == 13,
             "FiffEpochs/FiffEpochData: 13 fixed-length epochs like mne.make_fixed_length_epochs, averaged over 13");

Authors of this file

• Christoph Dinh <christoph.dinh@mne-cpp.org>