M2_arrayint rawMonomialOrderingToMatrix(const struct MonomialOrdering* mo)
{
bool base;
std::vector<int> mat;
M2_arrayint result = 0;
int component_is_before_row = 0;
int component_direction = 0;
if (monomialOrderingToMatrix(
*mo, mat, base, component_direction, component_is_before_row))
{
int top = static_cast<int>(mat.size());
result = M2_makearrayint(top + 3);
for (int i = 0; i < top; i++) result->array[i] = mat[i];
result->array[top] = (base ? 1 : 0);
result->array[top + 1] = component_direction;
result->array[top + 2] = component_is_before_row;
}
return result;
}
const Matrix * rawMGB(const Matrix *inputMatrix,
int reducer,
int spairGroupSize, // a value of 0 means let the algorithm choose
int nthreads,
M2_string logging)
{
const Ring *R = inputMatrix->get_ring();
const PolyRing *P = R->cast_to_PolyRing();
if (P == 0)
{
ERROR("expected a polynomial ring");
return 0;
}
if (nthreads < 0)
{
ERROR("mgb: expected a non-negative number of threads");
return 0;
}
int charac = P->charac();
int nvars = P->n_vars();
#if defined(HAVE_MATHICGB)
mgb::GroebnerConfiguration configuration(charac, nvars);
const auto reducerType = reducer == 0 ?
mgb::GroebnerConfiguration::ClassicReducer :
mgb::GroebnerConfiguration::MatrixReducer;
configuration.setReducer(reducerType);
configuration.setMaxSPairGroupSize(spairGroupSize);
configuration.setMaxThreadCount(nthreads);
std::string log(logging->array, logging->len);
configuration.setLogging(log.c_str());
std::vector<int> mat;
bool base_is_revlex = true;
// Now set the monomial ordering info
if (!monomialOrderingToMatrix(* P->getMonoid()->getMonomialOrdering(), mat, base_is_revlex))
{
ERROR("monomial ordering is not appropriate for Groebner basis computation");
return 0;
}
configuration.setMonomialOrder((base_is_revlex ?
mgb::GroebnerConfiguration::BaseOrder::ReverseLexicographicBaseOrder
: mgb::GroebnerConfiguration::BaseOrder::LexicographicBaseOrder),
mat);
#if 0
// Debug information
printf("Setting monomial order:");
for (size_t i=0; i<mat.size(); i++) printf("%d ", mat[i]);
printf("\n");
printf(" Base=%d\n", base_is_revlex);
#endif
mgb::GroebnerInputIdealStream input(configuration);
std::ostringstream computedStr;
mgb::IdealStreamLog<> computed(computedStr, charac, nvars);
mgb::IdealStreamChecker<decltype(computed)> checkedOut(computed);
matrixToStream(inputMatrix, input);
MatrixStream matStream(P);
// mgb::computeGroebnerBasis(input, checked);
mgb::computeGroebnerBasis(input, matStream);
const Matrix* result = matStream.value();
// rawDisplayMatrixStream(result);
return result;
#endif
return inputMatrix;
}