@Cache_this(limit=3, ignore_args=())
    def dK_dr_via_X(self, X, X2):
        #a convenience function, so we can cache dK_dr
        return self.dK_dr(self._scaled_dist(X, X2))
compute the derivative of K wrt X going through X
dataset/ETHPy150Open SheffieldML/GPy/GPy/kern/src/stationary.py/Stationary.dK_dr_via_X