mirror of
https://github.com/data61/MP-SPDZ.git
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445 lines
12 KiB
C++
445 lines
12 KiB
C++
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#include "FHE/Ring_Element.h"
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#include "Exceptions/Exceptions.h"
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#include "FHE/FFT.h"
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void reduce_step(vector<modp>& aa,int i,const FFT_Data& FFTD)
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{ modp temp=aa[i];
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for (int j=0; j<FFTD.phi_m(); j++)
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{
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if (FFTD.Phi()[j] > 0)
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for (int k = 0; k < FFTD.Phi()[j]; k++)
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Sub(aa[i-FFTD.phi_m()+j],aa[i-FFTD.phi_m()+j],temp,FFTD.get_prD());
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else
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for (int k = 0; k < abs(FFTD.Phi()[j]); k++)
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Add(aa[i-FFTD.phi_m()+j],aa[i-FFTD.phi_m()+j],temp,FFTD.get_prD());
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}
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}
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void reduce(vector<modp>& aa, int top, int bottom, const FFT_Data& FFTD)
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{
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for (int i = top - 1; i >= bottom; i--)
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reduce_step(aa, i, FFTD);
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}
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Ring_Element::Ring_Element(const FFT_Data& fftd,RepType r)
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{
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FFTD=&fftd;
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rep=r;
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assign_zero();
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}
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void Ring_Element::assign_zero()
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{
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element.resize((*FFTD).phi_m());
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ assignZero(element[i],(*FFTD).get_prD()); }
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}
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void Ring_Element::assign_one()
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{
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element.resize((*FFTD).phi_m());
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modp fill;
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if (rep==polynomial) { assignZero(fill,(*FFTD).get_prD()); }
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else { assignOne(fill,(*FFTD).get_prD()); }
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for (int i=1; i<(*FFTD).phi_m(); i++)
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{ element[i]=fill; }
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assignOne(element[0],(*FFTD).get_prD());
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}
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void Ring_Element::negate()
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{
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ Negate(element[i],element[i],(*FFTD).get_prD()); }
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}
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void add(Ring_Element& ans,const Ring_Element& a,const Ring_Element& b)
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{
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if (a.rep!=b.rep) { throw rep_mismatch(); }
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if (a.FFTD!=b.FFTD) { throw pr_mismatch(); }
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ans.partial_assign(a);
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for (int i=0; i<(*ans.FFTD).phi_m(); i++)
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{ Add(ans.element[i],a.element[i],b.element[i],(*a.FFTD).get_prD()); }
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}
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void sub(Ring_Element& ans,const Ring_Element& a,const Ring_Element& b)
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{
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if (a.rep!=b.rep) { throw rep_mismatch(); }
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if (a.FFTD!=b.FFTD) { throw pr_mismatch(); }
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ans.partial_assign(a);
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for (int i=0; i<(*ans.FFTD).phi_m(); i++)
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{ Sub(ans.element[i],a.element[i],b.element[i],(*a.FFTD).get_prD()); }
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}
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void mul(Ring_Element& ans,const Ring_Element& a,const Ring_Element& b)
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{
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if (a.rep!=b.rep) { throw rep_mismatch(); }
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if (a.FFTD!=b.FFTD) { throw pr_mismatch(); }
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ans.partial_assign(a);
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if (ans.rep==evaluation)
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{ // In evaluation representation, so we can just multiply componentwise
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for (int i=0; i<(*ans.FFTD).phi_m(); i++)
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{ Mul(ans.element[i],a.element[i],b.element[i],(*a.FFTD).get_prD()); }
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}
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else if ((*ans.FFTD).get_twop()!=0)
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{ // This is the case where m is not a power of two
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// Here we have to do a poly mult followed by a reduction
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// We could be clever (e.g. use Karatsuba etc), but instead
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// we do the school book method followed by term re-writing
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// School book mult
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vector<modp> aa(2*(*a.FFTD).phi_m());
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for (int i=0; i<2*(*a.FFTD).phi_m(); i++)
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{ assignZero(aa[i],(*a.FFTD).get_prD()); }
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modp temp;
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for (int i=0; i<(*a.FFTD).phi_m(); i++)
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{ for (int j=0; j<(*a.FFTD).phi_m(); j++)
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{ Mul(temp,a.element[i],b.element[j],(*a.FFTD).get_prD());
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int k=i+j;
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Add(aa[k],aa[k],temp,(*a.FFTD).get_prD());
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}
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}
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// Now apply reduction, assumes Ring.poly is monic
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reduce(aa, 2*(*a.FFTD).phi_m(), (*a.FFTD).phi_m(), *a.FFTD);
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// Now stick into answer
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for (int i=0; i<(*ans.FFTD).phi_m(); i++)
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{ ans.element[i]=aa[i]; }
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}
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else if ((*ans.FFTD).get_twop()==0)
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{ // m a power of two case
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Ring_Element aa(*ans.FFTD,ans.rep);
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modp temp;
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for (int i=0; i<(*ans.FFTD).phi_m(); i++)
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{ for (int j=0; j<(*ans.FFTD).phi_m(); j++)
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{ Mul(temp,a.element[i],b.element[j],(*a.FFTD).get_prD());
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int k=i+j;
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if (k>=(*ans.FFTD).phi_m())
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{ k-=(*ans.FFTD).phi_m();
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Negate(temp,temp,(*a.FFTD).get_prD());
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}
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Add(aa.element[k],aa.element[k],temp,(*a.FFTD).get_prD());
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}
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}
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ans=aa;
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}
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else
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{ throw not_implemented(); }
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}
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void mul(Ring_Element& ans,const Ring_Element& a,const modp& b)
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{
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ans.partial_assign(a);
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for (int i=0; i<(*ans.FFTD).phi_m(); i++)
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{ Mul(ans.element[i],a.element[i],b,(*a.FFTD).get_prD()); }
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}
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Ring_Element Ring_Element::mul_by_X_i(int j) const
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{
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Ring_Element ans;
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auto& a = *this;
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ans.partial_assign(a);
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if (ans.rep == evaluation)
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{
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modp xj, xj2;
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Power(xj, (*ans.FFTD).get_root(0), j, (*a.FFTD).get_prD());
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Sqr(xj2, xj, (*a.FFTD).get_prD());
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for (int i= 0; i < (*ans.FFTD).phi_m(); i++)
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{
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Mul(ans.element[i], a.element[i], xj, (*a.FFTD).get_prD());
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Mul(xj, xj, xj2, (*a.FFTD).get_prD());
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}
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}
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else
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{
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Ring_Element aa(*ans.FFTD, ans.rep);
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for (int i= 0; i < (*ans.FFTD).phi_m(); i++)
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{
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int k= j + i, s= 1;
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while (k >= (*ans.FFTD).phi_m())
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{
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k-= (*ans.FFTD).phi_m();
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s= -s;
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}
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if (s == 1)
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{
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aa.element[k]= a.element[i];
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}
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else
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{
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Negate(aa.element[k], a.element[i], (*a.FFTD).get_prD());
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}
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}
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ans= aa;
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}
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return ans;
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}
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void Ring_Element::randomize(PRNG& G,bool Diag)
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{
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if (Diag==false)
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{ for (int i=0; i<(*FFTD).phi_m(); i++)
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{ element[i].randomize(G,(*FFTD).get_prD()); }
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}
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else
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{ element[0].randomize(G,(*FFTD).get_prD());
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if (rep==polynomial)
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{ for (int i=1; i<(*FFTD).phi_m(); i++)
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{ assignZero(element[i],(*FFTD).get_prD()); }
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}
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else
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{ for (int i=1; i<(*FFTD).phi_m(); i++)
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{ element[i]=element[0]; }
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}
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}
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}
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void Ring_Element::change_rep(RepType r)
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{
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if (rep==r) { return; }
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if (r==evaluation)
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{ rep=evaluation;
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if ((*FFTD).get_twop()==0)
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{ // m a power of two variant
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FFT_Iter2(element,(*FFTD).phi_m(),(*FFTD).get_root(0),(*FFTD).get_prD());
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}
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else
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{ // Non m power of two variant and FFT enabled
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vector<modp> fft((*FFTD).m());
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BFFT(fft,element,*FFTD);
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ element[i]=fft[(*FFTD).p(i)]; }
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}
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}
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else
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{ rep=polynomial;
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if ((*FFTD).get_twop()==0)
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{ // m a power of two variant
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modp root2;
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Sqr(root2,(*FFTD).get_root(1),(*FFTD).get_prD());
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FFT_Iter(element, (*FFTD).phi_m(),root2,(*FFTD).get_prD());
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modp w;
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w = (*FFTD).get_iphi();
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ Mul(element[i], element[i], w, (*FFTD).get_prD());
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Mul(w, w, (*FFTD).get_root(1),(*FFTD).get_prD());
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}
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}
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else
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{ // Non power of 2 m variant and FFT enabled
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vector<modp> fft((*FFTD).m());
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for (int i=0; i<(*FFTD).m(); i++)
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{ assignZero(fft[i],(*FFTD).get_prD()); }
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ fft[(*FFTD).p(i)]=element[i]; }
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BFFT(fft,fft,*FFTD,false);
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// Need to reduce fft mod Phi_m
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reduce(fft, (*FFTD).m(), (*FFTD).phi_m(), *FFTD);
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ element[i]=fft[i]; }
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}
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}
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}
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bool Ring_Element::equals(const Ring_Element& a) const
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{
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if (rep!=a.rep) { throw rep_mismatch(); }
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if (*FFTD!=*a.FFTD) { throw pr_mismatch(); }
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ if (!areEqual(element[i],a.element[i],(*FFTD).get_prD())) { return false; } }
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return true;
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}
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void Ring_Element::from_vec(const vector<bigint>& v)
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{
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RepType t=rep;
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rep=polynomial;
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bigint tmp;
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{
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tmp = v[i];
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element[i].convert_destroy(tmp, FFTD->get_prD());
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}
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change_rep(t);
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// cout << "RE:from_vec<bigint>:: " << *this << endl;
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}
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void Ring_Element::from_vec(const vector<int>& v)
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{
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RepType t=rep;
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rep=polynomial;
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ to_modp(element[i],v[i],(*FFTD).get_prD()); }
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change_rep(t);
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// cout << "RE:from_vec<int>:: " << *this << endl;
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}
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ConversionIterator Ring_Element::get_iterator() const
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{
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if (rep != polynomial)
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throw runtime_error("simple iterator only available in polynomial represention");
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return {element, (*FFTD).get_prD()};
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}
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RingReadIterator Ring_Element::get_copy_iterator() const
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{
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return *this;
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}
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RingWriteIterator Ring_Element::get_write_iterator()
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{
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return *this;
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}
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vector<bigint> Ring_Element::to_vec_bigint() const
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{
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vector<bigint> v;
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to_vec_bigint(v);
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return v;
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}
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void Ring_Element::to_vec_bigint(vector<bigint>& v) const
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{
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v.resize(FFTD->phi_m());
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if (rep==polynomial)
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{ for (int i=0; i<(*FFTD).phi_m(); i++)
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{ to_bigint(v[i],element[i],(*FFTD).get_prD()); }
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}
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else
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{ Ring_Element a=*this;
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a.change_rep(polynomial);
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for (int i=0; i<(*FFTD).phi_m(); i++)
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{ to_bigint(v[i],a.element[i],(*FFTD).get_prD()); }
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}
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}
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modp Ring_Element::get_constant() const
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{
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if (rep==polynomial)
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{ return element[0]; }
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Ring_Element a=*this;
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a.change_rep(polynomial);
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return a.element[0];
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}
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void store(octetStream& o,const vector<modp>& v,const Zp_Data& ZpD)
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{
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ZpD.pack(o);
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o.store((int)v.size());
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for (unsigned int i=0; i<v.size(); i++)
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{ v[i].pack(o,ZpD); }
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}
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void get(octetStream& o,vector<modp>& v,const Zp_Data& ZpD)
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{
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Zp_Data check_Zpd;
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check_Zpd.unpack(o);
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if (check_Zpd != ZpD)
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throw runtime_error(
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"mismatch: " + to_string(check_Zpd.pr_bit_length) + "/"
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+ to_string(ZpD.pr_bit_length));
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unsigned int length;
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o.get(length);
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v.resize(length);
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for (unsigned int i=0; i<length; i++)
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{ v[i].unpack(o,ZpD); }
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}
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void Ring_Element::pack(octetStream& o) const
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{
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check_size();
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o.store(unsigned(rep));
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store(o,element,(*FFTD).get_prD());
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}
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void Ring_Element::unpack(octetStream& o)
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{
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unsigned int a;
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o.get(a);
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rep=(RepType) a;
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check_rep();
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get(o,element,(*FFTD).get_prD());
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check_size();
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}
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void Ring_Element::check_rep()
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{
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if (rep != evaluation and rep != polynomial)
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throw runtime_error("invalid representation");
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}
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void Ring_Element::check_size() const
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{
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if ((int)element.size() != FFTD->phi_m())
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throw runtime_error("invalid element size");
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}
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void Ring_Element::output(ostream& s) const
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{
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s.write((char*)&rep, sizeof(rep));
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auto size = element.size();
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s.write((char*)&size, sizeof(size));
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for (auto& x : element)
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x.output(s, FFTD->get_prD(), false);
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}
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void Ring_Element::input(istream& s)
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{
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s.read((char*)&rep, sizeof(rep));
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check_rep();
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auto size = element.size();
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s.read((char*)&size, sizeof(size));
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element.resize(size);
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for (auto& x : element)
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x.input(s, FFTD->get_prD(), false);
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}
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void Ring_Element::check(const FFT_Data& FFTD) const
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{
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if (&FFTD != this->FFTD)
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throw params_mismatch();
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}
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size_t Ring_Element::report_size(ReportType type) const
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{
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if (type == CAPACITY)
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return sizeof(modp) * element.capacity();
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else
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return sizeof(mp_limb_t) * (*FFTD).get_prD().get_t() * element.size();
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}
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template void Ring_Element::from(const Generator<bigint>& generator);
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template void Ring_Element::from(const Generator<int>& generator);
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