h.gf2bit

来自「强大的数学工具包」· GF2BIT 代码 · 共 37 行

                               * * * * * * *
                               *  GF2bit   *
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        "Galois-field element in characteristic 2, special bit 
         representation"
        SYNTAX: X = GF2bit(Y)

        Y is a sequence of 0 and 1.
        They are interpreted as coefficients of a polynomial in Z/2Z.
        (For example the string 100101 represents the Galois-field  
        element GF(A^5 + A^2 + 1) if 'A' is the specified variable.)

        X is assigned the expression corresponding to Y over the current
        Galois-field GF(2^n).

        GF(2^n) is specified by "curgf" or "curgf2bit".
        For additional information on working with the current Galois- 
        field, please type "? curgf" or "? curgf2bit".

        Remark: The structures over GF(2^n) are displayed on the screen 
                in polynomial representation. If you want to see the
                bit representation of an element of GF(2^n), please use
                putGF2bit (see "?putGF2bit").


        Example 1: (correct)

                GF2bit( 1011010 )


        Example 2: (incorrect)

                GF2bit( A^2+1 ) 

_ERR_NR_015