void Polynomial<int>::pseudo_div(
const Polynomial<int>& f, const Polynomial<int>& g,
Polynomial<int>& q, Polynomial<int>& r, int& D)
{
CGAL_NEF_TRACEN("pseudo_div "<<f<<" , "<< g);
int fd=f.degree(), gd=g.degree();
if ( fd<gd )
{ q = Polynomial<int>(0); r = f; D = 1;
CGAL_postcondition(Polynomial<int>(D)*f==q*g+r); return;
}
// now we know fd >= gd and f>=g
int qd=fd-gd, delta=qd+1, rd=fd;
{ q = Polynomial<int>( std::size_t(delta) ); }; // workaround for SUNPRO
int G = g[gd]; // highest order coeff of g
D = G; while (--delta) D*=G; // D = G^delta
Polynomial<int> res = Polynomial<int>(D)*f;
CGAL_NEF_TRACEN(" pseudo_div start "<<res<<" "<<qd<<" "<<q.degree());
while (qd >= 0) {
int F = res[rd]; // highest order coeff of res
int t = F/G; // ensured to be integer by multiplication of D
q.coeff(qd) = t; // store q coeff
res.minus_offsetmult(g,t,qd);
if (res.is_zero()) break;
rd = res.degree();
qd = rd - gd;
}
r = res;
CGAL_postcondition(Polynomial<int>(D)*f==q*g+r);
CGAL_NEF_TRACEN(" returning "<<q<<", "<<r<<", "<< D);
}
Polynomial::Polynomial(const Polynomial& rhs)
{
mMonomials.resize(rhs.degree() + 1, Monomial("0", 0));
for (int i = 0; i <= rhs.degree(); i++)
{
mMonomials[i] = rhs[i];
}
}
Polynomial Polynomial::operator *(Polynomial b) {
Polynomial ret(degree() + b.degree() - 1);
for (int i = 0; i < degree(); i++) {
for (int j = 0; j < b.degree(); j++) {
ret.coefficients[i + j] += (coefficients[i] * b.coefficients[j]);
}
}
return ret;
}
Polynomial Polynomial::operator+(Polynomial b) {
Polynomial ret = *this;
for (int i = 0; i < std::max(this->degree(), b.degree()); i++) {
if (i > this->degree()) {
ret.coefficients.push_back(b.coefficients[i]);
}
ret.coefficients[i] += i < b.degree() ? b.coefficients[i] : 0;
}
return ret;
}
bool Polynomial::operator ==(Polynomial b) {
int max = std::max(this->degree(), b.degree());
for (int i = 0; i < max; i++) {
if (!(this->coefficients[i] == b.coefficients[i]
|| (i >= b.degree() && this->coefficients[i] == 0)
|| (i >= this->degree() && b.coefficients[i] == 0))) {
return false;
}
}
return true;
}
Polynomial&
Polynomial::operator*=(const Polynomial& other)
{
Polynomial self = *this * other;
mMonomials.resize(self.degree() + 1, Monomial("0", 0));
for (int i = 0; i <= self.degree(); i++)
{
mMonomials[i] = self[i];
}
return *this;
}
Polynomial
Polynomial::operator*(const Polynomial& other) const
{
Polynomial result;
for (int i = 0; i <= degree() + other.degree(); i++)
{
for (int j = MAX(0, i - degree());
j <= MIN(other.degree(), i);
j++)
{
result += mMonomials[i-j] * other.mMonomials[j];
}
}
return result;
}
void Polynomial<int>::euclidean_div(
const Polynomial<int>& f, const Polynomial<int>& g,
Polynomial<int>& q, Polynomial<int>& r)
{
r = f; r.copy_on_write();
int rd=r.degree(), gd=g.degree(), qd;
if ( rd < gd ) { q = Polynomial<int>(int(0)); }
else { qd = rd-gd+1; q = Polynomial<int>(std::size_t(qd)); }
while ( rd >= gd && !(r.is_zero())) {
int S = r[rd] / g[gd];
qd = rd-gd;
q.coeff(qd) += S;
r.minus_offsetmult(g,S,qd);
rd = r.degree();
}
CGAL_postcondition( f==q*g+r );
}
inline Polynomial<eT>
gcd(const Polynomial<eT>& x, const Polynomial<eT>& y)
{
Polynomial<eT> r;
Polynomial<eT> u;
Polynomial<eT> v;
const int xdeg = x.degree();
const int ydeg = y.degree();
if(xdeg < 0 || ydeg < 0)
return std::move(u);
if((xdeg == 0 && x[0] == 0) || (ydeg == 0 && y[0] == 0))
{
u.resize(1);
u[0] = eT(0);
return std::move(u);
}
const bool maxo = (xdeg >= ydeg);
u = maxo ? x : y;
v = maxo ? y : x;
while(1)
{
r = u % v;
u = v;
v = r;
if(v.degree() == 0 && v[0] == 0)
break;
}
if(u.degree() == 0) //x and y are co-primes
u[0] = eT(1);
return std::move(u);
}
// doesn't return a remainder
// N.B. this function will break if there is a remainder
const Polynomial Polynomial::div( const Polynomial& rhs ) const {
Polynomial retVal;
if( degree() < rhs.degree() )
{
return retVal; // return 0
}
Polynomial rSide( *this );
int rDeg = rhs.degree();
double rCoeff = rhs._list.begin().getData().coeff;
itr_t it = rSide._list.begin();
while( 1 )
{
if( it == rSide._list.end() ) break;
int deg_diff = it.getData().degree() - rDeg;
if( deg_diff < 0 ) break; // TODO: check this condition, maybe need to put rest into remainder?
double coeff = it.getData().coeff / rCoeff;
Polynomial tmp;
Term multiplier( coeff, deg_diff );
retVal.addTerm( multiplier );
for( itr_t itt = rhs._list.begin(); itt != rhs._list.end(); ++itt )
{
Term res = itt.getData() * multiplier;
tmp.addTerm( res );
}
rSide = rSide.sub( tmp );
it = rSide._list.begin();
}
return retVal;
}
Polynomial Polynomial::operator*(const Polynomial& other) const
{
Polynomial result;
int n = (other.degree()) + degree();
double c = 0;
int i = 0;
for(int left = 0; left < size; left++){
for(int right = 0; right < other.size; right++){
c = coeff[left] * other.coeff[right];
i = left + right;
result[i] += c;
}
}
result.size = n + 1;
return result;
}
inline void
poly2mat(const Polynomial<eT>& p, Mat<eT>& m)
{
const uword n = p.degree();
m.set_size(n,n);
eT head = p[n];
for(uword i = 0; i < n-1; ++i)
{
m(i, i+1) = 1.0;
}
for(uword i = 0; i < n; ++i)
{
m(n-1, i) = -p[i]/head;
}
}
FiniteField::FiniteField(const Polynomial& irred) : p(irred.getMod()), k(irred.degree()), domain(irred.getDomain()), modulus(irred) {
//assert(k > 1 && "Use PrimeField if k==1");
assert(irred.isIrreducible());
}
