qc-ldpc码编程，围长为6，列重为3，无4环-The algorithm divides rows into three equal groups. The rows are then connnected to form a distance graph which is then transformed in to a matrix. Girth of six is maintained by avoiding four-cycles. No two rows are connected

QC-LDPC码生成矩阵编程，围长为12，无4环-The program searches for a girth 12 QC-LDPC code given size of sub-matrix, row and column weights. The configuration of sub-matrices could also be changed. The program offers flexibility in constructing girth-12 QC-LDPC codes