init_mean_cost# init_mean_cost(X: ndarray) → tuple[ndarray, ndarray, ndarray][source]# Precompute sums and weights for mean_cost. Parameters: Xnp.ndarray2D array. Returns: sumsnp.ndarrayCumulative sums of X. sums2np.ndarrayCumulative sums of X**2. weightsnp.ndarrayWeights for sums2 in the cost calculation.