pyriemann.utils.base.expm

pyriemann.utils.base.expm(C)

Exponential of SPD matrices.

The matrix exponential of a SPD matrix C is defined by:

\[\mathbf{D} = \mathbf{V} \exp{(\mathbf{\Lambda})} \mathbf{V}^\top\]

where \(\mathbf{\Lambda}\) is the diagonal matrix of eigenvalues and \(\mathbf{V}\) the eigenvectors of \(\mathbf{C}\).

Parameters
Cndarray, shape (…, n, n)

SPD matrices, at least 2D ndarray.

Returns
Dndarray, shape (…, n, n)

Matrix exponential of C.