Computational Results of Duadic Double Circulant Codes

Quadratic residue codes have been one of the most important classes of algebraic codes. They have been generalized into duadic codes and quadratic double circulant codes. In this paper we introduce a new subclass of double circulant codes, called duadic double circulant codes, which is a generalization of quadratic double circulant codes for prime lengths. This class generates optimal self-dual codes, optimal linear codes, and linear codes with the best known parameters in a systematic way. We describe a method to construct duadic double circulant codes using 4-cyclotomic cosets and give certain duadic double circulant codes over F2,F3,F4,F5, and F7. In particular, we find a new ternary self-dual [76, 38, 18] code and easily rediscover optimal binary self-dual codes with parameters [66, 33, 12], [68, 34, 12], [86, 43, 16], and [88, 44, 16] as well as a formally self-dual binary [82, 41, 14] code.