# pyriemann.utils.base.invsqrtm¶

pyriemann.utils.base.invsqrtm(C)

Inverse square root of SPD/HPD matrices.

The symmetric matrix inverse square root of a SPD/HPD matrix C is defined by:

$\mathbf{D} = \mathbf{V} \left( \mathbf{\Lambda} \right)^{-1/2} \mathbf{V}^H$

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 inverse square root of C.