1d3e25c3ad4835ee298675f557e4c78bc8501c74,GPflow/ekernels.py,RBF,eKxz,#RBF#Any#Any#Any#,24

Before Change

        q = tf.reduce_sum(smIvec * vec, [1]) // NxM

        det = tf.matrix_determinant(
            tf.expand_dims(eye(D), 0) + tf.reshape(lengthscales ** -2.0, (1, 1, -1)) * Xcov
        )  // N
        return self.variance * tf.expand_dims(det ** -0.5, 1) * tf.exp(-0.5 * q)

After Change

        lengthscales = self.lengthscales if self.ARD else tf.zeros((D,), dtype=float_type) + self.lengthscales

        vec = tf.expand_dims(Xmu, 2) - tf.expand_dims(tf.transpose(Z), 0)  // NxDxM
        chols = tf.cholesky(tf.expand_dims(tf.diag(lengthscales ** 2), 0) + Xcov)
        Lvec = tf.matrix_triangular_solve(chols, vec)
        q = tf.reduce_sum(Lvec ** 2, [1])

        chol_diags = tf.matrix_diag_part(chols)  // N x D
        half_log_dets = tf.reduce_sum(tf.log(chol_diags), 1) - tf.reduce_sum(tf.log(lengthscales))  // N,

        return self.variance * tf.exp(-0.5 * q - tf.expand_dims(half_log_dets, 1))

Instances