hasse_deriv1.m

在matlab中

function val = hasse_deriv1(g,x,r,m)

%
%
% Takes the r-th Hasse derivative of the polynomial g
%  over the finite field GF(2^m).

%[Is] = find(g~=0);

val = gf(0,m);

for ind1=(r+1):length(g)
   binom = nchoosek(ind1-1,r);
   if (binom - 2*floor(binom/2)==1)
%      [g(ind1) x^(ind1-1-r)]
      val = val + g(ind1) * x^(ind1-1 - r);
   end
end