fact: Definition sumproduct_init : 'M[R]_(m, n) * 'M[R]_(m, n) := let init (x : 'F_2) := \matrix_(m0 < m, n0 < n) W `(y !_ n0 | x) in (init 0, init 1).
imports: mathcomp(all_ssreflect ssralg fingroup finalg perm zmodp) mathcomp(matrix vector ssrnum) Reals Lra mathcomp(Rstruct) ssrR Reals_ext realType_ext ssr_ext ssralg_ext num_occ bigop_ext fdist channel pproba f2 linearcode subgraph_partition tanner tanner_partition hamming binary_symmetric_channel decoding channel_code summary checksum summary_tanner