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/* This code written by Franziska Hinkelmann is in the public domain */
#include "franzi-brp.hpp"
#include "matrix-con.hpp"
#include "matrix.hpp"
extern void testSPolynomial();
extern void gb(IntermediateBasis &F, int n);
brMonomial exponentsToLong(int nvars, const exponents exp)
{
brMonomial result = 0;
for (int i = 0; i < nvars; i++)
if (exp[i] != 0)
{
result += 1ul << (nvars - 1 - i);
// cout << "result " << result;
}
// cout << endl;
return result;
}
void longToExponents(int nvars, brMonomial mono, exponents exp)
{
// cout << "longToExponents " << mono << endl;
for (int i = 0; i < nvars; i++)
{
exp[nvars - i - 1] = ((mono & 1ul) ? 1 : 0);
mono >>= 1;
// cout << "after shift longToExponents " << mono << endl;
}
// for( int i=0; i < nvars; i++ )
// {
// cout << exp[i] << " ";
// }
// cout << endl;
//
}
IntermediateBasis BRPSfromMatrix(const Matrix *m)
{
const Ring *R = m->get_ring();
const PolynomialRing *P = R->cast_to_PolynomialRing();
assert(P != 0); // TODO: change this.
const Monoid *M = P->getMonoid();
int n = P->n_vars();
exponents exp = newarray_atomic(int, n);
IntermediateBasis F;
for (int i = 0; i < m->n_cols(); i++)
{
vec v = m->elem(i);
if (v == 0) continue;
BRP temp;
for (Nterm *f = v->coeff; f != 0; f = f->next)
{
M->to_expvector(f->monom, exp);
brMonomial mono = exponentsToLong(n, exp);
temp = temp + BRP(mono);
}
F[i] = temp;
}
freemem(exp);
return F;
}
const Matrix *BRPStoMatrix(const PolynomialRing *P, const IntermediateBasis &F)
{
MatrixConstructor C(P->make_FreeModule(1), 0);
const Monoid *M = P->getMonoid();
const Ring *K = P->getCoefficients();
int n = P->n_vars();
exponents exp = newarray_atomic(int, n);
monomial mon = M->make_one();
for (IntermediateBasis::const_iterator it = F.begin(); it != F.end(); ++it)
{
ring_elem f;
for (monomials::const_iterator it2 = it->second.m.begin();
it2 != it->second.m.end();
++it2)
{
brMonomial mono = *it2;
// cout << "a single mono in brpstoMatrix " << mono << endl;
longToExponents(n, mono, exp);
// for( int i=0; i < n; i++ )
// {
// cout << exp[i] << " ";
// }
// cout << endl;
M->from_expvector(exp, mon);
ring_elem g = P->make_flat_term(K->one(), mon);
P->add_to(f, g);
}
C.append(P->make_vec(0, f));
}
freemem(exp);
return C.to_matrix();
}
extern "C" const Matrix *rawGbBoolean(const Matrix *m)
{
IntermediateBasis F = BRPSfromMatrix(m);
// cout << "first BRP in F " << F.begin()->second << endl;
const Ring *R = m->get_ring();
const PolynomialRing *P = R->cast_to_PolynomialRing();
if (P == 0)
{
ERROR("expected a polynomial ring");
return 0;
}
if (P->characteristic() != 2)
{
ERROR("expected coefficient ring ZZ/2");
return 0;
}
if (not P->getCoefficientRing()->isFinitePrimeField())
{
ERROR("expected coefficient ring ZZ/2");
return 0;
}
int n = P->n_vars();
if (n > 64)
{
ERROR("Cannot handle more than 64 variables yet");
return 0;
}
gb(F, n);
// cout << "first BRP in F after gb() " << F.begin()->second << endl;
return BRPStoMatrix(P, F);
}
// Local Variables:
// compile-command: "make -C $M2BUILDDIR/Macaulay2/e "
// indent-tabs-mode: nil
// End:
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