Abstract: Double-loop networks have been widely studied as architecture for local area networks.Based on the works of Liu et al.a new algorithm to find h-tight（h≥0） optimal double-loop networks is presented，and is executed with VC++6.0.For any given N，s（1<s<N） can be found，so that G（N；1，s） is h-tight（h≥0）optimal.For any N≤108，it’s calculated that the number of h（0≤h≤7）tight optimal double-loop networks and its first N with h（0≤h≤7）tight optimal.According to the results of the experiments，some errors of an efficient algorithm are shown to find optimal double loop networks proposed by Augilo and Fiol.

Key words: double-loop networks, diameter, tight optimal, algorithm

摘要： 在刘焕平等人工作的基础上，给出一个改进的h（h≥0）紧优双环网络的构造算法。利用VC++6.0编程来实现这一算法，对任意给定N，找出s（1<s<N）使得双环网络G（N；1，s）h（h≥0）紧优。首次给出了N在一亿之内，所有h（0≤h≤7）紧优双环网的个数及对应h的最小N值。并根据实验所得数据，指出Augilo和Fiol的求紧优双环网络算法的不足与错误。

关键词: 双环网络, 直径, 紧优, 算法