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Reed–Muller codes are a family of linear error-correcting codes used in communications. Reed–Muller codes belong to the classes of locally testable codes and locally decodable codes, which is why they are useful in the design of probabilistically checkable proofs in computational complexity theory. They are named after Irving S. Reed and David E. Muller. Muller discovered the codes, and Reed proposed the majority logic decoding for the first time. Special cases of Reed–Muller codes include the Hadamard code, the Walsh–Hadamard code, and the Reed–Solomon code. Reed–Muller codes are listed as RM(''d'', ''r''), where ''d'' is the order of the code, and ''r'' determines the length of code, ''n'' = 2 ''r''. RM codes are related to binary functions on the field GF(2 ''r'') over the elements . RM(0, ''r'') codes are repetition codes of length ''n'' = 2 ''r'', rate and minimum distance ''d''min = ''n''. RM(1, ''r'') codes are parity check codes of length ''n'' = 2 ''r'', rate and minimum distance . RM(''r'' − 1, ''r'') codes are parity check codes of length ''n'' = 2 ''r''. RM(''r'' − 2, ''r'') codes are the family of extended Hamming codes of length ''n'' = 2 ''r'' with minimum distance ''d''min = 4.〔Trellis and Turbo Coding, C. Schlegel & L. Perez, Wiley Interscience, 2004, p149.〕 ==Construction== A generator matrix for a Reed–Muller code of length ''n'' = 2''d'' can be constructed as follows. Let us write: : Note that each member of the set X is a point in . We define in n-dimensional space the indicator vectors : on subsets by: : together with, also in , the binary operation : referred to as the ''wedge product'' (this wedge product is not to be confused with the wedge product defined in exterior algebra). Here, and are points in , and the operation is the usual multiplication in the field . is a ''d''-dimensional vector space over the field , so it is possible to write We define in ''n''-dimensional space the following vectors with length ''n'': ''v''0 = (1, 1, 1, 1, 1, 1, 1, 1) and : where the ''H''''i'' are hyperplanes in (with dimension d −1): : 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Reed–Muller code」の詳細全文を読む スポンサード リンク
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