In this paper

we present a measurement method of the real minimum Elartuning distance of several kinds of LDPC codes

including quasi-cyclic LDPC codes

pirotation LDPC codes

etc.The minimum distance is indirectly obtained by computing the cycles of the LDPC code.Since the complexity of computing the cycles is much lower than that of direct computing the minimum distance

the method is efficient to compute the minimum distance of the LDPC code.From one of simulation results

it shows that it takes about 77 minutes to compute a minimum distance of 24 for a rate 1/4 quasi-cyclic LDPC code using a common personal computer.