def parabolic_kernel()

in orbit/utils/kernels.py [0:0]

• 19 lines of code
• 4 McCabe index (conditional complexity)

def parabolic_kernel(x, x_i):
    # TODO: docstring
    N = len(x)
    M = len(x_i)
    k = np.zeros((N, M), dtype=np.double)

    # boundary case
    np_idx = np.where(x < x_i[0])
    if len(np_idx) > 0:
        k[np_idx, 0] = 1

    for m in range(M - 1):
        np_idx = np.where(np.logical_and(x >= x_i[m], x < x_i[m + 1]))
        total_dist = x_i[m + 1] - x_i[m]
        backward_dist = x[np_idx] - x_i[m]
        forward_dist = x_i[m + 1] - x[np_idx]
        k[np_idx, m] = 0.75 * (1 - (backward_dist / total_dist) ** 2)
        k[np_idx, m + 1] = 0.75 * (1 - (forward_dist / total_dist) ** 2)

    # boundary case
    np_idx = np.where(x >= x_i[M - 1])
    if len(np_idx) > 0:
        k[np_idx, M - 1] = 1

    # TODO: it is probably not needed
    k = k / np.sum(k, axis=1, keepdims=True)

    return k