void BuildIrred(GF2X& f, long n)
{
if (n <= 0)
Error("BuildIrred: n must be positive");
if (NTL_OVERFLOW(n, 1, 0)) Error("overflow in BuildIrred");
if (n == 1) {
SetX(f);
return;
}
GF2X g;
_ntl_ulong i;
i = 0;
do {
ConvertBits(g, 2*i+1);
SetCoeff(g, n);
i++;
} while (!IterIrredTest(g));
f = g;
}
NTL_CLIENT
#define NO_CARRY 0
#define CARRY 1
///////////////////////////////////////////////////////////////////////////
// return a modulus appropriate for F_q=F_{p^d}
void get_modulus(zz_pX& pi, int p, int d)
{
zz_p::init(p);
SetX(pi);
pi <<= d-1;
while (IterIrredTest(pi) == 0 && inc(pi,d-1) == 0)
;
assert(IterIrredTest(pi) == 1 && deg(pi) == d);
}
static
void BuildPrimePowerIrred(ZZ_pEX& f, long q, long e)
{
long n = power(q, e);
do {
random(f, n);
SetCoeff(f, n);
} while (!IterIrredTest(f));
}
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 BuildIrred(ZZ_pEX& f, long n)
{
if (n <= 0)
LogicError("BuildIrred: n must be positive");
if (n == 1) {
SetX(f);
return;
}
ZZ_pEX g;
do {
random(g, n);
SetCoeff(g, n);
} while (!IterIrredTest(g));
f = g;
}
void BuildIrred(GF2EX& f, long n)
{
if (n <= 0)
Error("BuildIrred: n must be positive");
if (NTL_OVERFLOW(n, 1, 0))
Error("overflow in BuildIrred");
if (n == 1) {
SetX(f);
return;
}
GF2EX g;
do {
random(g, n);
SetCoeff(g, n);
} while (!IterIrredTest(g));
f = g;
}
