tabu2.py 文件源码

def stochasticTwoOpt(perm):
    result = perm[:]  # make a copy
    size = len(result)
    p1, p2 = random.randrange(0, size), random.randrange(0, size)
    exclude = set([p1])
    if p1 == 0:
        exclude.add(size - 1)
    else:
        exclude.add(p1 - 1)

    if p1 == size - 1:
        exclude.add(0)
    else:
        exclude.add(p1 + 1)

    while p2 in exclude:
        p2 = random.randrange(0, size)

    if p2 < p1:
        p1, p2 = p2, p1

    result[p1:p2] = reversed(result[p1:p2])

    return result