pyriemann.geometry.geodesic.geodesic_thompson¶
- pyriemann.geometry.geodesic.geodesic_thompson(A, B, alpha=0.5)[source]¶
Thompson geodesic between SPD/HPD matrices.
The matrix at position \(\alpha\) on a possible Thompson geodesic between two SPD/HPD matrices \(\mathbf{A}\) and \(\mathbf{B}\) is given in [1].
\(\mathbf{C}\) is equal to \(\mathbf{A}\) if \(\alpha\) = 0, and \(\mathbf{B}\) if \(\alpha\) = 1.
- Parameters:
- Andarray, shape (…, n, n)
First SPD/HPD matrices.
- Bndarray, shape (…, n, n)
Second SPD/HPD matrices.
- alphafloat | ndarray, shape (…,), default=0.5
Position on the geodesic. If ndarray, one value per matrix pair.
Changed in version 0.12.
- Returns:
- Cndarray, shape (…, n, n)
SPD/HPD matrices on the Thompson geodesic.
See also
Notes
Added in version 0.10.
Changed in version 0.12: Add support for NumPy and PyTorch. Add support for array-valued alpha.
References
[1]Differential geometry with extreme eigenvalues in the positive semidefinite cone C. Mostajeran, N. Da Costa, G. Van Goffrier and R. Sepulchre. SIAM Journal on Matrix Analysis and Applications, 2024