  We point out an error in the paper "Linear Time Encoding of LDPC Codes" (by
Jin Lu and Jos\'e M. F. Moura, IEEE Trans). The paper claims to present a
linear time encoding algorithm for every LDPC code. We present a family of
counterexamples, and point out where the analysis fails. The algorithm in the
aforementioned paper fails to encode our counterexample, let alone in linear
time.

Computational Complexity