* Changed repo structure from src/ to src/pyfme

* Added aricraft folder with an empty file that will contain the test aircraft.
* Added some functions in utils/coordinates to change from body to local horizon coords and from local horizon coords to body (tested).

.gitignore

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+__pycache__
+.cache
+
+*.py[cod]

src/pyfme/__init__.py

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+
+

src/pyfme/utils/coordinates.py

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+# -*- coding: utf-8 -*-
+"""
+Frames of Reference orientation functions
+"""
+
+import numpy as np
+
+# Reassing for readability
+sin = np.sin
+cos = np.cos
+
+
+def check_theta_phi_psi_range(theta, phi, psi):
+    """Check theta, phi, psi values are inside the defined range. This
+    comprobation can also detect if the value of the angle is in degrees in
+    some cases.
+    """
+
+    theta_min, theta_max = (-np.pi/2, np.pi/2)
+    phi_min, phi_max = (-np.pi, np.pi)
+    psi_min, psi_max = (0, 2 * np.pi)
+
+    if not (theta_min <= theta <= theta_max):
+        raise ValueError('Theta value is not inside correct range')
+    elif not (phi_min <= phi <= phi_max):
+        raise ValueError('Phi value is not inside correct range')
+    elif not (psi_min <= phi <= psi_max):
+        raise ValueError('Psi value is not inside correct range')
+
+
+
+def body2hor(body_coords, theta, phi, psi):
+    """Transforms the vector coordinates in body frame of reference to local
+    horizon frame of reference.
+
+    Parameters
+    ----------
+    body_coords : array_like
+        3 dimensional vector with (x,y,z) coordinates in body axes.
+    theta : float
+        Pitch (or elevation) angle (rad).
+    phi : float
+        Bank angle (rad).
+    psi : float
+        Yaw (or azimuth) angle (rad)
+
+    Returns
+    -------
+    hor_coords : array_like
+        3 dimensional vector with (x,y,z) coordinates in local horizon axes.
+
+    Raises
+    ------
+    ValueError
+        If the values of the euler angles are outside the proper ranges.
+
+    See Also
+    --------
+    `hor2body` function.
+
+    Notes
+    -----
+    See [1] or [2] for frame of reference definition.
+    Note that in order to avoid ambiguities ranges in angles are limited to:
+
+    * -pi/2 <= theta <= pi/2
+    * -pi <= phi <= pi
+    * 0 <= psi <= 2*pi
+
+    References
+    ----------
+    .. [1] B. Etkin, "Dynamics of Atmospheric Flight," Courier Corporation,
+        pp. 104-120, 2012.
+    .. [2] Gómez Tierno, M.A. et al, "Mecánica del Vuelo," Garceta, pp. 1-12,
+        2012
+    """
+
+    check_theta_phi_psi_range(theta, phi, psi)
+
+    # Transformation matrix from body to local horizon
+    Lhb = np.array([
+                    [cos(theta) * cos(psi),
+                     sin(phi) * sin(theta) * cos(psi) - cos(phi) * sin(psi),
+                     cos(phi) * sin(theta) * cos(psi) + sin(phi) * sin(psi)],
+                    [cos(theta) * sin(psi),
+                     sin(phi) * sin(theta) * sin(psi) + cos(phi) * cos(psi),
+                     cos(phi) * sin(theta) * sin(psi) - sin(phi) * cos(psi)],
+                    [- sin(theta),
+                     sin(phi) * cos(theta),
+                     cos(phi) * cos(theta)]
+                    ])
+
+    hor_coords = Lhb.dot(body_coords)
+
+    return hor_coords
+
+
+def hor2body(hor_coords, theta, phi, psi):
+    """Transforms the vector coordinates in local horizon frame of reference
+    to body frame of reference.
+
+    Parameters
+    ----------
+    hor_coords : array_like
+        3 dimensional vector with (x,y,z) coordinates in local horizon axes.
+    theta : float
+        Pitch (or elevation) angle (rad).
+    phi : float
+        Bank angle (rad).
+    psi : float
+        Yaw (or azimuth) angle (rad)
+
+    Returns
+    -------
+    body_coords : array_like
+        3 dimensional vector with (x,y,z) coordinates in body axes.
+
+    Raises
+    ------
+    ValueError
+        If the values of the euler angles are outside the proper ranges.
+
+    See Also
+    --------
+    `body2hor` function.
+
+    Notes
+    -----
+    See [1] or [2] for frame of reference definition.
+    Note that in order to avoid ambiguities ranges in angles are limited to:
+
+    * -pi/2 <= theta <= pi/2
+    * -pi <= phi <= pi
+    * 0 <= psi <= 2*pi
+
+    References
+    ----------
+    .. [1] B. Etkin, "Dynamics of Atmospheric Flight," Courier Corporation,
+        pp. 104-120, 2012.
+    .. [2] Gómez Tierno, M.A. et al, "Mecánica del Vuelo," Garceta, pp. 1-12,
+        2012
+    """
+
+    check_theta_phi_psi_range(theta, phi, psi)
+
+    # Transformation matrix local horizon to body
+    Lbh = np.array([
+                    [cos(theta) * cos(psi),
+                     cos(theta) * sin(psi),
+                     - sin(theta)],
+                    [sin(phi) * sin(theta) * cos(psi) - cos(phi) * sin(psi),
+                     sin(phi) * sin(theta) * sin(psi) + cos(phi) * cos(psi),
+                     sin(phi) * cos(theta)],
+                    [cos(phi) * sin(theta) * cos(psi) + sin(phi) * sin(psi),
+                     cos(phi) * sin(theta) * sin(psi) - sin(phi) * cos(psi),
+                     cos(phi) * cos(theta)]
+                    ])
+
+    body_coords = Lbh.dot(hor_coords)
+
+    return body_coords

src/pyfme/utils/tests/test_utils.py

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+# -*- coding: utf-8 -*-
+"""
+Frames of Reference orientation test functions
+"""
+import pytest
+
+import numpy as np
+from numpy.testing import (assert_equal, assert_almost_equal,
+                           assert_array_equal, assert_array_almost_equal)
+
+
+from pyfme.utils.coordinates import (body2hor, hor2body,
+                                     check_theta_phi_psi_range)
+
+
+def test_check_theta_phi_psi_range():
+
+    wrong_values = (3 * np.pi, - 3 * np.pi)
+
+    for value in wrong_values:
+        # 0 is always a correct value
+        angles = [0, 0, 0]
+        for ii in range(3):
+            angles[ii] = value
+            with pytest.raises(ValueError):
+                check_theta_phi_psi_range(*angles)
+
+
+def test_body2hor():
+
+    # Test with a pitch rotation
+    vector_body = np.array([1, 1, 1])
+    theta, phi, psi = np.deg2rad(45), 0, 0
+
+    vector_hor = body2hor(vector_body, theta, phi, psi)
+
+    vector_hor_expected = np.array([2 * 0.70710678118654757, 1, 0])
+
+    assert_array_almost_equal(vector_hor, vector_hor_expected)
+
+    # Test with a roll rotation
+    vector_body = np.array([1, 1, 1])
+    theta, phi, psi = 0, np.deg2rad(45), 0
+
+    vector_hor = body2hor(vector_body, theta, phi, psi)
+
+    vector_hor_expected = np.array([1, 0, 2 * 0.70710678118654757])
+
+    assert_array_almost_equal(vector_hor, vector_hor_expected)
+
+    # Test with a yaw rotation
+    vector_body = np.array([1, 1, 1])
+    theta, phi, psi = 0, 0, np.deg2rad(45)
+
+    vector_hor = body2hor(vector_body, theta, phi, psi)
+
+    vector_hor_expected = np.array([0, 2 * 0.70710678118654757, 1])
+
+    assert_array_almost_equal(vector_hor, vector_hor_expected)
+
+
+def test_hor2body():
+
+    # Test with a pitch rotation
+    vector_hor = np.array([2 * 0.70710678118654757,  1, 0])
+    theta, phi, psi = np.deg2rad(45), 0, 0
+
+    vector_body_expected = np.array([1, 1, 1])
+
+    vector_body = hor2body(vector_hor, theta, phi, psi)
+
+    assert_array_almost_equal(vector_body, vector_body_expected)
+
+    # Test with a roll rotation
+    vector_hor = np.array([1, 0, 2 * 0.70710678118654757])
+    theta, phi, psi = 0, np.deg2rad(45), 0
+
+    vector_body_expected = np.array([1, 1, 1])
+
+    vector_body = hor2body(vector_hor, theta, phi, psi)
+
+    assert_array_almost_equal(vector_body, vector_body_expected)
+
+    # Test with a yaw rotation
+    vector_hor = np.array([0, 2 * 0.70710678118654757, 1])
+    theta, phi, psi = 0, 0, np.deg2rad(45)
+
+    vector_body_expected = np.array([1, 1, 1])
+
+    vector_body = hor2body(vector_hor, theta, phi, psi)
+
+    assert_array_almost_equal(vector_body, vector_body_expected)