LDPC码即低密度奇偶校验码（Low Density Parity Check Code，LDPC），这是LDPC仿真中稀疏矩阵生成程序，我花了好几天的时间搞懂，并做了注释。

-LDPC codes that low-density parity check codes (Low Density Parity Check Code, LDPC), which is generated sparse matrix LDPC simulation program, I spent a few days time they get to know and do the comments.