18.9 LogFFE

LogFFE( z )
LogFFE( z, r )

In the first form LogFFE returns the discrete logarithm of the element z in a finite field with respect to the root FieldFFE(z).root. An error is signalled if z is zero.

In the second form LogFFE returns the discrete logarithm of the element z in a finite field with respect to the root r. An error is signalled if z is zero, or if z is not a power of r.

The discrete logarithm of an element z with respect to a root r is the smallest nonnegative integer i such that r^i = z.

    gap> LogFFE( Z(409)^116 );
    116
    gap> LogFFE( Z(409)^116, Z(409)^2 );
    58 

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