import tensorflow as tf


    if not white:
        q_mu = tf.matrix_triangular_solve(Luu, q_mu, lower=True)
        Luu_tiled = tf.tile(Luu[None, :, :], [num_func, 1, 1])  # remove line once issue 216 is fixed
        q_sqrt_r = tf.matrix_triangular_solve(Luu_tiled, q_sqrt_r, lower=True)

    Li_eKuf = tf.matrix_triangular_solve(Luu, eKuf, lower=True)  # M x N
    fmean = tf.matmul(Li_eKuf, q_mu, transpose_a=True)
