loss_fr

loss.loss_fr(sigma_hat, sigma)[source]

Squared Frobenius norm scaled by 1/p. Same as np.linalg.norm(sigma_hat - sigma, 'fro')**2 *1/p.

Parameters
sigma_hatnumpy.ndarray

The covariance matrix estimate using the estimator of interest.

sigmanumpy.ndarray

The (true) population covariance matrix.

Returns
outfloat

The minimum variance loss.

Notes

The loss function is given by:

\[\mathcal{L}_{n}^{\mathrm{FR}}\left(\widehat{\Sigma}_{n}, \Sigma_{n}\right):=\frac{1}{p} \operatorname{Tr}\left[\left(\widehat{\Sigma}_{n} -\Sigma_{n}\right)^{2}\right]\]