# pyriemann.utils.base.expm¶

pyriemann.utils.base.expm(C)

Exponential of SPD/HPD matrices.

The symmetric matrix exponential of a SPD/HPD matrix C is defined by:

$\mathbf{D} = \mathbf{V} \exp{(\mathbf{\Lambda})} \mathbf{V}^H$

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

Parameters
Cndarray, shape (…, n, n)

SPD/HPD matrices, at least 2D ndarray.

Returns
Dndarray, shape (…, n, n)

Matrix exponential of C.