Source code for felupe.math._spatial

# -*- coding: utf-8 -*-
"""
This file is part of FElupe.

FElupe is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

FElupe is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with FElupe.  If not, see <http://www.gnu.org/licenses/>.
"""

import numpy as np




def rotation_matrix(alpha_deg, dim=3, axis=0):
    """Rotation matrix with given rotation axis and dimension (2d or 3d).

    Parameters
    ----------
    alpha_deg : int
        Rotation angle in degree.
    dim : int, optional (default is 3)
        Dimension of the rotation matrix.
    axis : int, optional (default is 0)
        Rotation axis.

    Returns
    -------
    rotation_matrix : ndarray
        Rotation matrix of dim 2 or 3 with given rotation axis.
    """

    a = np.deg2rad(alpha_deg)
    rotation_matrix = np.array([[np.cos(a), -np.sin(a)], [np.sin(a), np.cos(a)]])

    if dim == 3:
        if axis == 1:
            rotation_matrix = rotation_matrix.T
        rotation_matrix = np.insert(rotation_matrix, [axis], np.zeros((1, 2)), axis=0)
        rotation_matrix = np.insert(rotation_matrix, [axis], np.zeros((3, 1)), axis=1)
        rotation_matrix[axis, axis] = 1

    return rotation_matrix