Girth 4 test for LDPC codes

We need to know that Girth 4 of H will lead to a poor BER performance. The program can test whether

Recently, we find some published programs for the construction of LDPC codes have not concerned the Girth test problem, which will not the implementation of LDPC Codec to have good decoding BER. Thus, we publish a simple program to provide a tool for the girth 4 test of LDPC codes.

Input a parity check matrix H with the format of the example in the program, the program can determine whether it has
girth 4.

Ref:
[1] Y. Xiao, M -H Lee,Low complexity IMO-LDPC CDMA systems over multipath channels, IEICE Transactions on Communications, v E89-B, n 5, May, 2006, p 1713-1717
[2] J. Fan, Y. Xiao, A method of counting the number of cycles in LDPC codes, 8th International Conference on Signal Processing, ICSP 2006,Volume: 3, ISBN: 0-7803-9737-1, Digital Object Identifier: 10.1109/ICOSP.2006.345906

The papers [1] and [2] can be downloaded from Web site of IEICE and IEEE Explore.