def Kdiag(self, X):
        """Compute the diagonal of the covariance matrix associated to X."""
        ret = np.empty(X.shape[0])
        ret[:] = self.variance
        return ret
def Kdiag ( self , X ) : ret = np . empty ( X . shape [ 0 ] ) ret [ : ] = self . variance return ret
Compute the diagonal of the covariance matrix associated to X.