// factor n into a*b using Pollard Rho method
// pre-condition: n>1
inline void PollardRho(ZZ& a, ZZ& b, const ZZ& n,
const ZZ& bnd=ZZ::zero()) {
ZZ_pBak bak;
bak.save();
ZZ_p::init(n);
ZZ d;
ZZ_p x1;
random(x1);
ZZ_p x2(x1);
ZZ end(IsZero(bnd)?5*SqrRoot(SqrRoot(n)):2*SqrRoot(bnd));
for (; !IsZero(end); --end) {
x1 = x1*x1 + 1;
x2 = x2*x2 + 1;
x2 = x2*x2 + 1;
GCD(d,n,rep(x2-x1));
if ((d>1)&&(d<n)) {
a=d; b=n/d;
return;
}
}
// failure
a=1; b=n;
}
void main() {
int cnt = 0;
set<pair<int, int>> S;
for (long b = 5; b <= 640; b += 5) {
for (long t = 1; t <= 11328; t += 1) {
// if ((59 * b / 5 + t) % 5 != 0) continue;
for (long h = 41; h <= 3776; h += 41) {
long A = 6 * ((59 * b + t * 5) * 41 + 450 * h);
long B = (b + t + h) * 41 * 25;
long g = GCD(A, B);
B /= g, A /= g;
if ((59. / 41) * (59. / 41) * B / A > 1.) continue;
if (is_sqr(A) && is_sqr(B)) {
A = SqrRoot(A), B = SqrRoot(B);
if (b * 59 * B % (A * 5) != 0) continue;
if (t % A != 0) continue;
if (h * 90 * B % (A * 41) != 0) continue;
pair<int, int> s = {B, A};
if (!S.count(s)) {
S.insert(s);
++cnt;
print("#{}: b = {}, t = {}, h = {}, m = {}/{}, ans = {}\n", cnt, b, t, h, B * 59, A * 41, B * 59. / (A * 41.));
}
}
}
}
}
if (S.count({25, 36}))
print("good!\n");
}
void SqrRoot(RR& z, const RR& a)
{
if (sign(a) < 0)
ArithmeticError("RR: attempt to take square root of negative number");
if (IsZero(a)) {
clear(z);
return;
}
RR t;
ZZ T1, T2;
long k;
k = 2*RR::prec - NumBits(a.x) + 1;
if (k < 0) k = 0;
if ((a.e - k) & 1) k++;
LeftShift(T1, a.x, k);
// since k >= 2*prec - bits(a) + 1, T1 has at least 2*prec+1 bits,
// thus T1 >= 2^(2*prec)
SqrRoot(t.x, T1); // t.x >= 2^prec thus t.x contains the round bit
t.e = (a.e - k)/2;
sqr(T2, t.x);
// T1-T2 is the (lower part of the) sticky bit
normalize(z, t, T2 < T1);
}
void Comp3Mod(zz_pX& x1, zz_pX& x2, zz_pX& x3,
const zz_pX& g1, const zz_pX& g2, const zz_pX& g3,
const zz_pX& h, const zz_pXModulus& F)
{
long m = SqrRoot(g1.rep.length() + g2.rep.length() + g3.rep.length());
if (m == 0) {
clear(x1);
clear(x2);
clear(x3);
return;
}
zz_pXArgument A;
build(A, h, F, m);
zz_pX xx1, xx2, xx3;
CompMod(xx1, g1, A, F);
CompMod(xx2, g2, A, F);
CompMod(xx3, g3, A, F);
x1 = xx1;
x2 = xx2;
x3 = xx3;
}
bool ProvePrime(const ZZ& _n) {
ZZ n(_n);
if (n<0)
abs(n,n);
if (n<=1)
return 0;
if (n<=1000000) {
// n is small so use trial division to check primality
long ln = to_long(n);
long end = to_long(SqrRoot(n));
PrimeSeq s;
for (long p=s.next(); p<=end; p=s.next())
if ((ln%p)==0)
return 0;
return 1;
}
// check small primes
PrimeSeq s;
for (long p=s.next(); p<1000; p=s.next())
if (divide(n,p))
return 0;
// obviously, something is missing here!
return ProbPrime(n);
}
NTL_START_IMPL
static
long CharPolyBound(const mat_ZZ& a)
// This bound is computed via interpolation
// through complex roots of unity.
{
long n = a.NumRows();
long i;
ZZ res, t1, t2;
set(res);
for (i = 0; i < n; i++) {
InnerProduct(t1, a[i], a[i]);
abs(t2, a[i][i]);
mul(t2, t2, 2);
add(t2, t2, 1);
add(t1, t1, t2);
if (t1 > 1) {
SqrRoot(t1, t1);
add(t1, t1, 1);
}
mul(res, res, t1);
}
return NumBits(res);
}
static
void GenerateBabySteps(GF2EX& h1, const GF2EX& f, const GF2EX& h, long k,
long verbose)
{
double t;
if (verbose) { cerr << "generating baby steps..."; t = GetTime(); }
GF2EXModulus F;
build(F, f);
GF2EXArgument H;
#if 0
double n2 = sqrt(double(F.n));
double n4 = sqrt(n2);
double n34 = n2*n4;
long sz = long(ceil(n34/sqrt(sqrt(2.0))));
#else
long sz = 2*SqrRoot(F.n);
#endif
build(H, h, F, sz);
h1 = h;
long i;
long HexOutput = GF2X::HexOutput;
GF2X::HexOutput = 1;
if (!use_files) {
BabyStepFile.kill();
BabyStepFile.SetLength(k-1);
}
for (i = 1; i <= k-1; i++) {
if (use_files) {
ofstream s;
OpenWrite(s, FileName(GF2EX_stem, "baby", i));
s << h1 << "\n";
s.close();
}
else
BabyStepFile(i) = h1;
CompMod(h1, h1, H, F);
if (verbose) cerr << "+";
}
if (verbose)
cerr << (GetTime()-t) << "\n";
GF2X::HexOutput = HexOutput;
}
long UseComposeFrobenius(long d, long n)
{
long i;
i = 1;
while (i <= d) i = i << 1;
i = i >> 1;
i = i >> 1;
long m = 1;
long dz;
if (n == 2) {
dz = 1;
}
else {
while (i) {
long m1 = 2*m;
if (i & d) m1++;
if (m1 >= NTL_BITS_PER_LONG-1 || (1L << m1) >= n) break;
m = m1;
i = i >> 1;
}
dz = 1L << m;
}
long rootn = SqrRoot(n);
long cnt = 0;
if (i) {
cnt += SqrRoot(dz+1);
i = i >> 1;
}
while (i) {
cnt += rootn;
i = i >> 1;
}
return 4*cnt <= d;
}
void SqrRootPrec(RR& x, const RR& a, long p)
{
if (p < 1 || NTL_OVERFLOW(p, 1, 0))
Error("SqrRootPrec: bad precsion");
long old_p = RR::prec;
RR::prec = p;
SqrRoot(x, a);
RR::prec = old_p;
}
// generate only matrices of the form s(X^{g^i})->s(X), but not all of them.
// For a generator g whose order is larger than bound, generate only enough
// matrices for the giant-step/baby-step procedures (2*sqrt(ord(g))of them).
void addSome1DMatrices(FHESecKey& sKey, long bound, long keyID)
{
const FHEcontext &context = sKey.getContext();
long m = context.zMStar.getM();
// key-switching matrices for the automorphisms
for (long i = 0; i < (long)context.zMStar.numOfGens(); i++) {
// For generators of small order, add all the powers
if (bound >= (long)context.zMStar.OrderOf(i))
for (long j = 1; j < (long)context.zMStar.OrderOf(i); j++) {
long val = PowerMod(context.zMStar.ZmStarGen(i), j, m); // val = g^j
// From s(X^val) to s(X)
sKey.GenKeySWmatrix(1, val, keyID, keyID);
if (!context.zMStar.SameOrd(i))
// also from s(X^{1/val}) to s(X)
sKey.GenKeySWmatrix(1, InvMod(val,m), keyID, keyID);
}
else { // For generators of large order, add only some of the powers
long num = SqrRoot(context.zMStar.OrderOf(i)); // floor(ord^{1/2})
if (num*num < (long) context.zMStar.OrderOf(i)) num++; // ceil(ord^{1/2})
// VJS: the above two lines replaces the following inexact calculation
// with an exact calculation
// long num = ceil(sqrt((double)context.zMStar.OrderOf(i)));
for (long j=1; j <= num; j++) { // Add matrices for g^j and g^{j*num}
long val1 = PowerMod(context.zMStar.ZmStarGen(i), j, m); // g^j
long val2 = PowerMod(context.zMStar.ZmStarGen(i),num*j,m);// g^{j*num}
if (j < num) {
sKey.GenKeySWmatrix(1, val1, keyID, keyID);
sKey.GenKeySWmatrix(1, val2, keyID, keyID);
}
if (!context.zMStar.SameOrd(i)) {
// sKey.GenKeySWmatrix(1, InvMod(val1,m), keyID, keyID);
sKey.GenKeySWmatrix(1, InvMod(val2,m), keyID, keyID);
}
}
// VJS: experimantal feature...because the replication code
// uses rotations by -1, -2, -4, -8, we add a few
// of these as well...only the small ones are important,
// and we only need them if SameOrd(i)...
// Note: we do indeed get a nontrivial speed-up
if (context.zMStar.SameOrd(i)) {
for (long k = 1; k <= num; k = 2*k) {
long j = context.zMStar.OrderOf(i) - k;
long val = PowerMod(context.zMStar.ZmStarGen(i), j, m); // val = g^j
sKey.GenKeySWmatrix(1, val, keyID, keyID);
}
}
}
}
sKey.setKeySwitchMap(); // re-compute the key-switching map
}
void SqrRootPrec(RR& x, const RR& a, long p)
{
if (p < 1)
LogicError("SqrRootPrec: bad precsion");
if (NTL_OVERFLOW(p, 1, 0))
ResourceError("SqrRootPrec: bad precsion");
RRPush push;
RR::prec = p;
SqrRoot(x, a);
}
NTL_CLIENT
#include "FHE.h"
long KSGiantStepSize(long D)
{
//OLD: assert(D > 0);
helib::assertTrue<helib::InvalidArgument>(D > 0l, "Step size must be positive");
long g = SqrRoot(D);
if (g*g < D) g++; // g = ceiling(sqrt(D))
return g;
}
static
void GenerateBabySteps(ZZ_pEX& h1, const ZZ_pEX& f, const ZZ_pEX& h, long k,
FileList& flist, long verbose)
{
double t;
if (verbose) { cerr << "generating baby steps..."; t = GetTime(); }
ZZ_pEXModulus F;
build(F, f);
ZZ_pEXArgument H;
#if 0
double n2 = sqrt(double(F.n));
double n4 = sqrt(n2);
double n34 = n2*n4;
long sz = long(ceil(n34/sqrt(sqrt(2.0))));
#else
long sz = 2*SqrRoot(F.n);
#endif
build(H, h, F, sz);
h1 = h;
long i;
if (!use_files) {
(*BabyStepFile).SetLength(k-1);
}
for (i = 1; i <= k-1; i++) {
if (use_files) {
ofstream s;
OpenWrite(s, FileName("baby", i), flist);
s << h1 << "\n";
CloseWrite(s);
}
else
(*BabyStepFile)(i) = h1;
CompMod(h1, h1, H, F);
if (verbose) cerr << "+";
}
if (verbose)
cerr << (GetTime()-t) << "\n";
}
static
void GenerateGiantSteps(const ZZ_pX& f, const ZZ_pX& h, long l, long verbose)
{
double t;
if (verbose) { cerr << "generating giant steps..."; t = GetTime(); }
ZZ_pXModulus F;
build(F, f);
ZZ_pXArgument H;
build(H, h, F, 2*SqrRoot(F.n));
ZZ_pX h1;
h1 = h;
long i;
if (!use_files) {
GiantStepFile.kill();
GiantStepFile.SetLength(l);
}
for (i = 1; i <= l-1; i++) {
if (use_files) {
ofstream s;
OpenWrite(s, FileName(ZZ_pX_stem, "giant", i));
s << h1 << "\n";
s.close();
}
else
GiantStepFile(i) = h1;
CompMod(h1, h1, H, F);
if (verbose) cerr << "+";
}
if (use_files) {
ofstream s;
OpenWrite(s, FileName(ZZ_pX_stem, "giant", i));
s << h1 << "\n";
s.close();
}
else
GiantStepFile(i) = h1;
if (verbose)
cerr << (GetTime()-t) << "\n";
}
static
void hadamard(ZZ& num_bound, ZZ& den_bound,
const mat_ZZ& A, const vec_ZZ& b)
{
long n = A.NumRows();
if (n == 0) Error("internal error: hadamard with n = 0");
ZZ b_len, min_A_len, prod, t1;
InnerProduct(min_A_len, A[0], A[0]);
prod = min_A_len;
long i;
for (i = 1; i < n; i++) {
InnerProduct(t1, A[i], A[i]);
if (t1 < min_A_len)
min_A_len = t1;
mul(prod, prod, t1);
}
if (min_A_len == 0) {
num_bound = 0;
den_bound = 0;
return;
}
InnerProduct(b_len, b, b);
div(t1, prod, min_A_len);
mul(t1, t1, b_len);
SqrRoot(num_bound, t1);
SqrRoot(den_bound, prod);
}
void CompMod(zz_pX& x, const zz_pX& g, const zz_pX& h, const zz_pXModulus& F)
// x = g(h) mod f
{
long m = SqrRoot(g.rep.length());
if (m == 0) {
clear(x);
return;
}
zz_pXArgument A;
build(A, h, F, m);
CompMod(x, g, A, F);
}
void ProjectPowers(vec_zz_p& x, const vec_zz_p& a, long k,
const zz_pX& h, const zz_pXModulus& F)
{
if (a.length() > F.n || k < 0) Error("ProjectPowers: bad args");
if (k == 0) {
x.SetLength(0);
return;
}
long m = SqrRoot(k);
zz_pXArgument H;
build(H, h, F, m);
ProjectPowers(x, a, k, H, F);
}
static
long DetBound(const mat_ZZ& a)
{
long n = a.NumRows();
long i;
ZZ res, t1;
set(res);
for (i = 0; i < n; i++) {
InnerProduct(t1, a[i], a[i]);
if (t1 > 1) {
SqrRoot(t1, t1);
add(t1, t1, 1);
}
mul(res, res, t1);
}
return NumBits(res);
}
static
void GenerateBabySteps(ZZ_pX& h1, const ZZ_pX& f, const ZZ_pX& h, long k,
FileList& flist, long verbose)
{
double t;
if (verbose) { cerr << "generating baby steps..."; t = GetTime(); }
ZZ_pXModulus F;
build(F, f);
ZZ_pXArgument H;
build(H, h, F, 2*SqrRoot(F.n));
h1 = h;
long i;
if (!use_files) {
(*BabyStepFile).SetLength(k-1);
}
for (i = 1; i <= k-1; i++) {
if (use_files) {
ofstream s;
OpenWrite(s, FileName("baby", i), flist);
s << h1 << "\n";
CloseWrite(s);
}
else
(*BabyStepFile)(i) = h1;
CompMod(h1, h1, H, F);
if (verbose) cerr << "+";
}
if (verbose)
cerr << (GetTime()-t) << "\n";
}
// ECM primitive
void ECM(ZZ& q, const ZZ& n, const ZZ& _bnd, double failure_prob,
bool verbose) {
ZZ bnd;
SqrRoot(bnd,n);
if (_bnd>0 && _bnd<bnd)
bnd=_bnd;
long B1,B2,D;
double prob;
ECM_parameters(B1,B2,prob,D,NumBits(bnd),NumBits(n));
if (verbose)
std::cout<<"ECM: bnd="<<NumBits(bnd)<<"bits B1="<<B1<<" B2="<<B2
<<" D="<<D<<" prob="<<prob<<std::endl;
if (failure_prob<=0) {
// run "forever"
if (verbose)
std::cout<<"ECM: expected ncurves="<<(1/prob)<<std::endl;
ECM(q,n,NTL_MAX_LONG,B1,B2,D,verbose);
}
else if (failure_prob>=1) {
// run on one curve
ECM(q,n,1,B1,B2,D,verbose);
}
else {
// run just the right number of times
// failure_prob = (1-prob)^ncurves;
double ncurves_d;
if (prob<0.1)
ncurves_d = to_double(log(failure_prob)/log1p(to_RR(-prob)));
else
ncurves_d = log(failure_prob)/log(1-prob);
long ncurves = ncurves_d<=1 ? 1 :
(ncurves_d>=NTL_MAX_LONG ? NTL_MAX_LONG : (long)ncurves_d);
if (verbose)
std::cout<<"ECM: good_prob="<<prob<<" failure_prob="<<failure_prob
<<" ncurves="<<ncurves<<std::endl;
ECM(q,n,ncurves,B1,B2,D,verbose);
}
}
void Comp2Mod(ZZ_pX& x1, ZZ_pX& x2, const ZZ_pX& g1, const ZZ_pX& g2,
const ZZ_pX& h, const ZZ_pXModulus& F)
{
long m = SqrRoot(g1.rep.length() + g2.rep.length());
if (m == 0) {
clear(x1);
clear(x2);
return;
}
ZZ_pXArgument A;
build(A, h, F, m);
ZZ_pX xx1, xx2;
CompMod(xx1, g1, A, F);
CompMod(xx2, g2, A, F);
x1 = xx1;
x2 = xx2;
}
long IsFFTPrime(long n, long& w)
{
long m, x, y, z;
long j, k;
if (n <= 1 || n >= NTL_SP_BOUND) return 0;
if (n % 2 == 0) return 0;
if (n % 3 == 0) return 0;
if (n % 5 == 0) return 0;
if (n % 7 == 0) return 0;
m = n - 1;
k = 0;
while ((m & 1) == 0) {
m = m >> 1;
k++;
}
for (;;) {
x = RandomBnd(n);
if (x == 0) continue;
z = PowerMod(x, m, n);
if (z == 1) continue;
x = z;
j = 0;
do {
y = z;
z = MulMod(y, y, n);
j++;
} while (j != k && z != 1);
if (z != 1 || y != n-1) return 0;
if (j == k)
break;
}
/* x^{2^k} = 1 mod n, x^{2^{k-1}} = -1 mod n */
long TrialBound;
TrialBound = m >> k;
if (TrialBound > 0) {
if (!ProbPrime(n, 5)) return 0;
/* we have to do trial division by special numbers */
TrialBound = SqrRoot(TrialBound);
long a, b;
for (a = 1; a <= TrialBound; a++) {
b = (a << k) + 1;
if (n % b == 0) return 0;
}
}
/* n is an FFT prime */
for (j = NTL_FFTMaxRoot; j < k; j++)
x = MulMod(x, x, n);
w = x;
return 1;
}
void main() {
R = SqrRoot(m);
int cnt = 0;
for (long i = 1; m / i > R; ++i)
basis[++cnt] = m / i;
for (int i = R; i; --i)
basis[++cnt] = i;
// for (int i = 1; i <= cnt; ++i) {
// if (get_index(basis[i]) != i)
// print("!!! {} {}\n", get_index(basis[i]), i);
// }
for (int i = 1; i <= cnt; ++i) {
num_primes[i] = basis[i] - 1;
}
// for (int i = 1; i < cnt; ++i) {
// for (int v = basis[i + 1] + 1; v <= basis[i]; ++v)
// if (v > R && ProbPrime(v))
// f[basis[i]] += 2;
// }
// f[1] = 1;
// for (int i = cnt - 1; i; --i) {
// f[basis[i]] += f[basis[i + 1]];
// // print("init {} = {}\n", basis[i], f[basis[i]]);
// }
// long ans = 0;
// for (int i = 1; i <= m; ++i) {
// ans += m / i;
// }
// print("bf = {}\n", ans);
for (long x = 2; x <= R; ++x) {
if (ProbPrime(x)) {
print("current = {}\n", x);
for (int i = 1; i <= cnt; ++i) {
long y = basis[i];
if (x * x > y)
break;
auto a = num_primes[get_index(y / x)];
auto b = num_primes[get_index(x - 1)];
num_primes[i] -= a - b;
}
}
}
for (int i = 1; i <= cnt; ++i) {
num_primes[i] %= MOD;
// print("{} {}\n", basis[i], num_primes[i]);
}
for (int i = 1; i <= cnt; ++i) {
f[i] = 1;
// if (basis[i] >= R) {
// f[i] += 2 * (num_primes[get_index(basis[i])] - num_primes[R]);
// }
// print("init {} {}\n", basis[i], f[i]);
}
for (long p = R; p; --p) {
if (ProbPrime(p)) {
print("current = {}\n", p);
int t = p > n ? 0 : get_power(p, n);
for (int e = 0; e <= 60; ++e)
g[e] = (e + 1) * (t + 1) + t * (t + 1) / 2;
for (int i = 1; i <= cnt; ++i) {
long y = basis[i];
if (t == 0 && p * p > y)
break;
long v = 0; // 2 * (num_primes[get_index(y)] - num_primes[p]);
for (int e = 0; y; ++e) {
v += real_f(y, p) * g[e] % MOD;
y /= p;
}
if (basis[i] >= p)
v -= 2 * (num_primes[i] - num_primes[get_index(p)] + 1) % MOD;
f[i] = (v + MOD) % MOD;
// print("update {} = {}\n", basis[i], v);
}
}
}
print("ans = {}\n", real_f(m, 1));
}
static
void GenerateGiantSteps(const ZZ_pEX& f, const ZZ_pEX& h, long l, long verbose)
{
double t;
if (verbose) { cerr << "generating giant steps..."; t = GetTime(); }
ZZ_pEXModulus F;
build(F, f);
ZZ_pEXArgument H;
#if 0
double n2 = sqrt(double(F.n));
double n4 = sqrt(n2);
double n34 = n2*n4;
long sz = long(ceil(n34/sqrt(sqrt(2.0))));
#else
long sz = 2*SqrRoot(F.n);
#endif
build(H, h, F, sz);
ZZ_pEX h1;
h1 = h;
long i;
if (!use_files) {
GiantStepFile.kill();
GiantStepFile.SetLength(l);
}
for (i = 1; i <= l-1; i++) {
if (use_files) {
ofstream s;
OpenWrite(s, FileName(ZZ_pEX_stem, "giant", i));
s << h1 << "\n";
s.close();
}
else
GiantStepFile(i) = h1;
CompMod(h1, h1, H, F);
if (verbose) cerr << "+";
}
if (use_files) {
ofstream s;
OpenWrite(s, FileName(ZZ_pEX_stem, "giant", i));
s << h1 << "\n";
s.close();
}
else
GiantStepFile(i) = h1;
if (verbose)
cerr << (GetTime()-t) << "\n";
}
// general purpose factoring method
void factor(vec_pair_ZZ_long& factors, const ZZ& _n,
const ZZ& bnd, double failure_prob,
bool verbose) {
ZZ n(_n);
if (n<=1) {
abs(n,n);
if (n<=1) {
factors.SetLength(0);
return;
}
}
// upper bound on size of smallest prime factor
ZZ upper_bound;
SqrRoot(upper_bound,n);
if (bnd>0 && bnd<upper_bound)
upper_bound=bnd;
// figure out appropriate lower_bound for trial division
long B1,B2,D;
double prob;
ECM_parameters(B1,B2,prob,D,NumBits(upper_bound),NumBits(n));
ZZ lower_bound;
conv(lower_bound,max(B2,1<<14));
if (lower_bound>upper_bound)
lower_bound=upper_bound;
// start factoring with trial division
TrialDivision(factors,n,n,to_long(lower_bound));
if (IsOne(n))
return;
if (upper_bound<=lower_bound || ProbPrime_notd(n)) {
addFactor(factors,n);
return;
}
/* n is composite and smallest prime factor is assumed to be such that
* lower_bound < factor <= upper_bound
*
* Ramp-up to searching for factors of size upper_bound. This is a good
* idea in cases where we have no idea what size factors N might have,
* but we don't want to spend too much time doing this.
*/
for(lower_bound<<=4; lower_bound<upper_bound; lower_bound<<=4) {
ZZ q;
ECM(q,n,lower_bound,1,verbose); // one curve only
if (!IsOne(q)) {
div(n,n,q);
if (n<q) swap(n,q);
// q is small factor, n is large factor
if (ProbPrime_notd(q))
addFactor(factors,q);
else
factor_r(factors,q,bnd,failure_prob,verbose);
if (ProbPrime_notd(n)) {
addFactor(factors,n);
return;
}
// new upper_bound
SqrRoot(upper_bound,n);
if (bnd>0 && bnd<upper_bound)
upper_bound=bnd;
}
}
// search for factors of size bnd
factor_r(factors,n,bnd,failure_prob,verbose);
}
void DDF(vec_pair_ZZ_pX_long& factors, const ZZ_pX& ff, const ZZ_pX& hh,
long verbose)
{
ZZ_pX f = ff;
ZZ_pX h = hh;
if (!IsOne(LeadCoeff(f)))
Error("DDF: bad args");
factors.SetLength(0);
if (deg(f) == 0)
return;
if (deg(f) == 1) {
AddFactor(factors, f, 1, verbose);
return;
}
long CompTableSize = 2*SqrRoot(deg(f));
long GCDTableSize = ZZ_pX_BlockingFactor;
ZZ_pXModulus F;
build(F, f);
ZZ_pXArgument H;
build(H, h, F, min(CompTableSize, deg(f)));
long i, d, limit, old_n;
ZZ_pX g, X;
vec_ZZ_pX tbl(INIT_SIZE, GCDTableSize);
SetX(X);
i = 0;
g = h;
d = 1;
limit = GCDTableSize;
while (2*d <= deg(f)) {
old_n = deg(f);
sub(tbl[i], g, X);
i++;
if (i == limit) {
ProcessTable(f, factors, F, i, tbl, d, verbose);
i = 0;
}
d = d + 1;
if (2*d <= deg(f)) {
// we need to go further
if (deg(f) < old_n) {
// f has changed
build(F, f);
rem(h, h, f);
rem(g, g, f);
build(H, h, F, min(CompTableSize, deg(f)));
}
CompMod(g, g, H, F);
}
}
ProcessTable(f, factors, F, i, tbl, d-1, verbose);
if (!IsOne(f)) AddFactor(factors, f, deg(f), verbose);
}
bool is_sqr(int x) {
int t = SqrRoot(x);
return x == t * t;
}
long IterIrredTest(const ZZ_pEX& f)
{
if (deg(f) <= 0) return 0;
if (deg(f) == 1) return 1;
ZZ_pEXModulus F;
build(F, f);
ZZ_pEX h;
FrobeniusMap(h, F);
long CompTableSize = 2*SqrRoot(deg(f));
ZZ_pEXArgument H;
build(H, h, F, CompTableSize);
long i, d, limit, limit_sqr;
ZZ_pEX g, X, t, prod;
SetX(X);
i = 0;
g = h;
d = 1;
limit = 2;
limit_sqr = limit*limit;
set(prod);
while (2*d <= deg(f)) {
sub(t, g, X);
MulMod(prod, prod, t, F);
i++;
if (i == limit_sqr) {
GCD(t, f, prod);
if (!IsOne(t)) return 0;
set(prod);
limit++;
limit_sqr = limit*limit;
i = 0;
}
d = d + 1;
if (2*d <= deg(f)) {
CompMod(g, g, H, F);
}
}
if (i > 0) {
GCD(t, f, prod);
if (!IsOne(t)) return 0;
}
return 1;
}
