中文摘要：

应用Chen等提出的研究线性分组码校验矩阵与Tanner图中圈的关系的方法,证明了围长为2k的校验矩阵中满足一定条件的k行组合与其Tanner图中最短圈的一一对应关系.由这一结论,对Chen等提出的计算Tanner图中最短圈数量的算法加以改进,减少一个运算步骤,而仍然得到同样准确的结果.

英文摘要：

By the method for investigating the relation between parity-check matrixes and cycles of associated Tanner graphs proposed by Chen et al., the one-to-one correspondence between k-rowcombinations satisfying a certain condition in a parity-check matrix of grith k and shortest cycles in the associated Tanner graph is proved. As a consequence, the algorithm for counting the shortest cycels of Tanner graphs proposed by Chen et al. is improved. The improved algorithm is as accurate as the original one while omitting one of the main steps.