the matlab program checks for cycles that are of the legnth 4.it is a useful program to check if the cycles in your LDPC code are to short thus causing BER errors

针对LDPC码在理论和实现两方面分别进行了较深的研究。深入了解了LDPC码编码方法、译码方法以及性能等知识，重点研究了用MATLAB如何构造奇偶校验矩阵、如何编码和如何解码的算法，而且实现了在相同码率、信噪比下LDPC码性能与卷积码性能的对比。-LDPC codes for both theory and implementation were carried out deeper study. In-depth understanding of the LDPC coding method,

ldpc码的编解码实现，实现了图像的灰度化并进一步用于视频监视控，课程设计时编写的matlab程序代码。- Codec ldpc code implementation Achieve a grayscale image and further control for video surveillance, Course designed to prepare the matlab program code.