Could you show what you are doing to get the statement "However, I cannot reproduce this matrix via composition; i.e. by multiplying the underlying rotation matrices.". I would guess something involving the `*` operator instead of `@`, but guessing probably won't help you solve your issue.
-Joe On Tue, Jan 31, 2017 at 7:56 PM, Seb <splu...@gmail.com> wrote: > Hello, > > I'm trying to compose Euler rotation matrices shown in > https://en.wikipedia.org/wiki/Euler_angles#Rotation_matrix. For > example, The Z1Y2X3 Tait-Bryan rotation shown in the table can be > represented in Numpy using the function: > > def z1y2x3(alpha, beta, gamma): > """Rotation matrix given Euler angles""" > return np.array([[np.cos(alpha) * np.cos(beta), > np.cos(alpha) * np.sin(beta) * np.sin(gamma) - > np.cos(gamma) * np.sin(alpha), > np.sin(alpha) * np.sin(gamma) + > np.cos(alpha) * np.cos(gamma) * np.sin(beta)], > [np.cos(beta) * np.sin(alpha), > np.cos(alpha) * np.cos(gamma) + > np.sin(alpha) * np.sin(beta) * np.sin(gamma), > np.cos(gamma) * np.sin(alpha) * np.sin(beta) - > np.cos(alpha) * np.sin(gamma)], > [-np.sin(beta), np.cos(beta) * np.sin(gamma), > np.cos(beta) * np.cos(gamma)]]) > > which given alpha, beta, gamma as: > > angles = np.radians(np.array([30, 20, 10])) > > returns the following matrix: > > In [31]: z1y2x3(angles[0], angles[1], angles[2]) > Out[31]: > > array([[ 0.81379768, -0.44096961, 0.37852231], > [ 0.46984631, 0.88256412, 0.01802831], > [-0.34202014, 0.16317591, 0.92541658]]) > > If I understand correctly, one should be able to compose this matrix by > multiplying the rotation matrices that it is made of. However, I cannot > reproduce this matrix via composition; i.e. by multiplying the > underlying rotation matrices. Any tips would be appreciated. > > -- > Seb > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > https://mail.scipy.org/mailman/listinfo/numpy-discussion >
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