65.40 IsEquivalent

IsEquivalent( C_1, C_2 )

IsEquivalent returns true if C_1 and C_2 are equi-valent codes. This is the case if C_1 can be obtained from C_2 by carrying out column permutations. GUAVA only handles binary codes. The external program desauto from J.S. Leon is used to compute the isomorphism between the codes. If C_1 and C_2 are equal, they are also equivalent.

Note that the algorithm is very slow for non-linear codes.

    gap> H := GeneratorPolCode([1,1,0,1]*Z(2), 7, GF(2));
    a cyclic [7,4,1..3]1 code defined by generator polynomial over GF(2)
    gap> H = HammingCode(3, GF(2));
    false
    gap> IsEquivalent(H, HammingCode(3, GF(2)));
    true                        # H is equivalent to a Hamming code
    gap> CodeIsomorphism(H, HammingCode(3, GF(2)));
    (3,4)(5,6,7) 

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