CASA Function: GoppaPrepareSa
Initialize Sakata's procedure for 1-point AG-codes.
Calling Sequence:
- Sak := GoppaPrepareSa(Code)
- Sak := GoppaPrepareSa(Code, baseMethod)
Parameters:
- Code : casa/finite/Goppa/primary
- A one point primary Goppa code whose nongap semi- group is spanned by 2 elements.
- baseMethod : string
- Method for determining basis needed, passed to DivBasisL.
Result:
- Sak : function
- A list containing all information you need for decoding using Sakata's algorithm which can be computed once for a code. .
Description:
- Performes the initializaton step for using Sakata's algorithm for one-point codes.
- The current implementation is only for one point Goppa codes with 2 generaters. The returned function can be used with SakataDecode.
Examples:
> infolevel[`casa/finite`] := 5;
> C1 := finiteCurve(x^3 + y^2 + y, finiteField(4));
> H1 := GoppaPrimary(C1, "affine", 4);
> Sak := GoppaPrepareSa(H1):
> w := [1 $ (H1["n"]-1), 0 ];
> c := SakataDecode(w, H1, Sak);
See Also:
[CASA]
[GoppaPrimary]
[SakataDecode]
[DivBasisL]
[GoppaPrepareDu]
[GoppaPrepareSV]