void Ctxt::multiplyBy2(const Ctxt& other1, const Ctxt& other2)
{
// Special case: if *this is empty then do nothing
if (this->isEmpty()) return;
long lvl = findBaseLevel();
long lvl1 = other1.findBaseLevel();
long lvl2 = other2.findBaseLevel();
if (lvl<lvl1 && lvl<lvl2){ // if both others at higher levels than this,
Ctxt tmp = other1; // multiply others by each other, then by this
if (&other1 == &other2) tmp *= tmp; // squaring rather than multiplication
else tmp *= other2;
*this *= tmp;
}
else if (lvl<lvl2) { // lvl1<=lvl<lvl2, multiply by other2, then by other1
*this *= other2;
*this *= other1;
}
else { // multiply first by other1, then by other2
*this *= other1;
*this *= other2;
}
reLinearize(); // re-linearize after all the multiplications
}
void Ctxt::multiplyBy2(const Ctxt& other1, const Ctxt& other2)
{
FHE_TIMER_START;
// Special case: if *this is empty then do nothing
if (this->isEmpty()) return;
long lvl = findBaseLevel();
long lvl1 = other1.findBaseLevel();
long lvl2 = other2.findBaseLevel();
if (lvl<lvl1 && lvl<lvl2){ // if both others at higher levels than this,
Ctxt tmp = other1; // multiply others by each other, then by this
if (&other1 == &other2) tmp *= tmp; // squaring rather than multiplication
else tmp *= other2;
*this *= tmp;
reLinearize(); // re-linearize after all the multiplications
return;
}
const Ctxt *first, *second;
if (lvl<lvl2) { // lvl1<=lvl<lvl2, multiply by other2, then by other1
first = &other2;
second = &other1;
}
else { // multiply first by other1, then by other2
first = &other1;
second = &other2;
}
if (this == second) { // handle pointer collision
Ctxt tmp = *second;
*this *= *first;
*this *= tmp;
if (this == first) // cubing operation
noiseVar *= 3; // a correction factor due to dependency
else
noiseVar *= 2; // a correction factor due to dependency
} else {
*this *= *first;
*this *= *second;
}
reLinearize(); // re-linearize after all the multiplications
}
void decryptAndPrint(ostream& s, const Ctxt& ctxt, const FHESecKey& sk,
const EncryptedArray& ea, long flags)
{
const FHEcontext& context = ctxt.getContext();
xdouble noiseEst = sqrt(ctxt.getNoiseVar());
xdouble modulus = xexp(context.logOfProduct(ctxt.getPrimeSet()));
vector<ZZX> ptxt;
ZZX p, pp;
sk.Decrypt(p, ctxt, pp);
s << "plaintext space mod "<<ctxt.getPtxtSpace()
<< ", level="<<ctxt.findBaseLevel()
<< ", \n |noise|=q*" << (coeffsL2Norm(pp)/modulus)
<< ", |noiseEst|=q*" << (noiseEst/modulus)
<<endl;
if (flags & FLAG_PRINT_ZZX) {
s << " before mod-p reduction=";
printZZX(s,pp) <<endl;
}
if (flags & FLAG_PRINT_POLY) {
s << " after mod-p reduction=";
printZZX(s,p) <<endl;
}
if (flags & FLAG_PRINT_VEC) {
ea.decode(ptxt, p);
if (ea.getAlMod().getTag() == PA_zz_p_tag
&& ctxt.getPtxtSpace() != ea.getAlMod().getPPowR()) {
long g = GCD(ctxt.getPtxtSpace(), ea.getAlMod().getPPowR());
for (long i=0; i<ea.size(); i++)
PolyRed(ptxt[i], g, true);
}
s << " decoded to ";
if (deg(p) < 40) // just pring the whole thing
s << ptxt << endl;
else if (ptxt.size()==1) // a single slot
printZZX(s, ptxt[0]) <<endl;
else { // print first and last slots
printZZX(s, ptxt[0],20) << "--";
printZZX(s, ptxt[ptxt.size()-1], 20) <<endl;
}
}
}
