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angles

Module: core

Category: mat3dvaluator

Type string: "angles"

Parameters

Name Description Default Units
theta theta 0 []
phi phi 90 []

Description

The angles mat3d valuator uses spherical angles to set up three perpendicular vectors to produce a orthonormal matrix.

  • theta : the azimuth angle (angle in xy plane and \(0\leqslant\theta<2\pi\))
  • phi : declination angle (angle with respect to the z-axis and \(0\leqslant\phi\leqslant\pi\))

The first vector is defined via,

\[ \mathbf{e}_{r}=\cos\theta\sin\phi\,\mathbf{e}_{1}+\sin\theta\sin\phi\,\mathbf{e}_{2}+\cos\phi\,\mathbf{e}_{3} \]

The second and third vectors are defined as follows,

\[ \mathbf{e}_{\theta}=-\sin\theta\,\mathbf{e}_{1}+\cos\theta\,\mathbf{e}_{2} \]
\[ \mathbf{e}_{\phi}=-\cos\theta\cos\phi\,\mathbf{e}_{1}-\sin\theta\cos\phi\,\mathbf{e}_{2}+\sin\phi\,\mathbf{e}_{\phi} \]

The matrix is formed by using these three vectors as columns.

\[ \mathbf{Q}=\left[ \mathbf{e}_{r} | \mathbf{e}_{\theta} | \mathbf{e}_{\phi} \right] \]