from_q

DCM.from_q(q: ndarray) → ndarray

Synonym of method from_quaternion().

Parameters:

q (numpy.ndarray) – Quaternion

Returns:

R – 3-by-3 direction cosine matrix

Return type:

numpy.ndarray

Examples

>>> R = DCM()
>>> R.from_q([0.70710678, 0.0, 0.70710678, 0.0])
array([[-2.22044605e-16,  0.00000000e+00,  1.00000000e+00],
       [ 0.00000000e+00,  1.00000000e+00,  0.00000000e+00],
       [-1.00000000e+00,  0.00000000e+00, -2.22044605e-16]])

Non-normalized quaternions will be normalized and transformed too.

>>> R.from_q([1, 0.0, 1, 0.0])
array([[ 2.22044605e-16,  0.00000000e+00,  1.00000000e+00],
       [ 0.00000000e+00,  1.00000000e+00,  0.00000000e+00],
       [-1.00000000e+00,  0.00000000e+00,  2.22044605e-16]])

A list (or a Numpy array) with N quaternions will return an N-by-3-by-3 array with the corresponding DCMs.

>>> R.from_q([[1, 0.0, 1, 0.0], [1.0, -1.0, 0.0, 1.0], [0.0, 0.0, -1.0, 1.0]])
array([[[ 2.22044605e-16,  0.00000000e+00,  1.00000000e+00],
        [ 0.00000000e+00,  1.00000000e+00,  0.00000000e+00],
        [-1.00000000e+00,  0.00000000e+00,  2.22044605e-16]],

       [[ 3.33333333e-01, -6.66666667e-01, -6.66666667e-01],
        [ 6.66666667e-01, -3.33333333e-01,  6.66666667e-01],
        [-6.66666667e-01, -6.66666667e-01,  3.33333333e-01]],

       [[-1.00000000e+00, -0.00000000e+00,  0.00000000e+00],
        [ 0.00000000e+00,  2.22044605e-16, -1.00000000e+00],
        [ 0.00000000e+00, -1.00000000e+00,  2.22044605e-16]]])