Source code for pycartool.lf.leadfield

# -*- coding: utf-8 -*-
# Authors: Victor Férat <victor.ferat@live.fr>
#
# License: BSD (3-clause)
import struct

import numpy as np


def read_lf(filename):
    """Read Cartool leadfield (``.lf``) file.

    Parameters
    ----------
    filename : str or file-like
        The leadfield file (``.lf``) to read.

    Returns
    -------
    leadfield_matrix : `~numpy.array`
        The leadfield matrix. shape(``n_channels``, ``n_sources``, ``3``).
    """
    with open(filename, "rb") as f:
        byte = f.read(4)
        number_of_electrodes = struct.unpack("i", byte)[0]
        byte = f.read(4)
        number_of_solution_points = struct.unpack("i", byte)[0]
        buf = f.read(number_of_electrodes * number_of_solution_points * 8)
        data = np.frombuffer(buf, dtype=np.double)
    number_of_points = int(number_of_solution_points / 3)
    leadfield_matrix = data.reshape(number_of_electrodes, number_of_points, 3)
    return leadfield_matrix