static
long FindTrinom(long n)
{
if (n < 2) Error("tri--bad n");
long k;
for (k = 1; k <= n/2; k++)
if (IterIrredTest(1 + GF2X(k,1) + GF2X(n,1)))
return k;
return 0;
}
static
long FindPent(long n, long& kk2, long& kk1)
{
if (n < 4) Error("pent--bad n");
long k1, k2, k3;
for (k3 = 3; k3 < n; k3++)
for (k2 = 2; k2 < k3; k2++)
for (k1 = 1; k1 < k2; k1++)
if (IterIrredTest(1+GF2X(k1,1)+GF2X(k2,1)+GF2X(k3,1)+GF2X(n,1))) {
kk2 = k2;
kk1 = k1;
return k3;
}
return 0;
}
void buildLinPolyMatrix(mat_GF2E& M, long p)
{
assert(p == 2);
long d = GF2E::degree();
M.SetDims(d, d);
for (long j = 0; j < d; j++)
conv(M[0][j], GF2X(j, 1));
for (long i = 1; i < d; i++)
for (long j = 0; j < d; j++)
M[i][j] = power(M[i-1][j], p);
}
void applyLinPoly(GF2E& beta, const vec_GF2E& C, const GF2E& alpha, long p)
{
long d = GF2E::degree();
assert(d == C.length());
GF2E gamma, res;
gamma = to_GF2E(GF2X(1, 1));
res = C[0]*alpha;
for (long i = 1; i < d; i++) {
gamma = power(gamma, p);
res += C[i]*to_GF2E(CompMod(rep(alpha), rep(gamma), GF2E::modulus()));
}
beta = res;
}
