def dKdiag_dtheta(self, dL_dKdiag, X, target):
        target[0] += np.sum(dL_dKdiag)
Gradient of diagonal of covariance with respect to parameters.
dataset/ETHPy150Open SheffieldML/GPy/GPy/kern/src/todo/gibbs.py/Gibbs.dKdiag_dtheta