pyriemann.utils.tangentspace.untangent_space(T, Cref, *, metric='riemann')

Transform tangent vectors back to SPD matrices.

Transform tangent vectors back to SPD matrices, according to a reference matrix Cref and to a specific exponential map.

Tndarray, shape (…, n_channels * (n_channels + 1) / 2)

Tangent vectors.

Crefndarray, shape (n_channels, n_channels)

The reference SPD matrix.

metricstring, default=’riemann’

The metric used for exponential map, can be: ‘euclid’, ‘logeuclid’, ‘riemann’.

Xndarray, shape (…, n_channels, n_channels)

SPD matrices.