// Find the next prime and add it to the chain
long FHEcontext::AddPrime(long initialP, long delta, bool special,
bool findRoot)
{
// long twoM = 2 * zMStar.getM();
// assert((initialP % twoM == 1) && (delta % twoM == 0));
// NOTE: this assertion will fail for the half-prime in ALT_CRT
long p = initialP;
do {
p += delta; // delta could be positive or negative
}
while (p>initialP/16 && p<NTL_SP_BOUND && !(ProbPrime(p) && !inChain(p)));
if (p<=initialP/16 || p>=NTL_SP_BOUND) return 0; // no prime found
long i = moduli.size(); // The index of the new prime in the list
moduli.push_back( Cmodulus(zMStar, p, findRoot ? 0 : 1) );
if (special)
specialPrimes.insert(i);
else
ctxtPrimes.insert(i);
return p;
}
// Find the next prime and add it to the chain
long FHEcontext::AddPrime(long initialP, long delta, bool special)
{
long p = initialP;
do { p += delta; } // delta could be positive or negative
while (p>initialP/16 && p<NTL_SP_BOUND && !(ProbPrime(p) && !inChain(p)));
if (p<=initialP/16 || p>=NTL_SP_BOUND) return 0; // no prime found
long i = moduli.size(); // The index of the new prime in the list
moduli.push_back( Cmodulus(zMStar, p, 0) );
if (special)
specialPrimes.insert(i);
else
ctxtPrimes.insert(i);
return p;
}
long FHEcontext::AddFFTPrime(bool special)
{
zz_pBak bak; bak.save(); // Backup the NTL context
do {
zz_p::FFTInit(fftPrimeCount);
fftPrimeCount++;
} while (inChain(zz_p::modulus()));
long i = moduli.size(); // The index of the new prime in the list
long p = zz_p::modulus();
moduli.push_back( Cmodulus(zMStar, 0, 1) ); // a dummy Cmodulus object
if (special)
specialPrimes.insert(i);
else
ctxtPrimes.insert(i);
return p;
}
