nullSpace() [2/5]

size_t MatrixOps::nullSpace ( const DMatQQFlint & A, DMatQQFlint & result_nullspace )

inline

Definition at line 1127 of file mat-linalg.hpp.

{
  fmpz_mat_t m1;
  fmpz_mat_t m2;
  fmpz_mat_init(m1, A.numRows(), A.numColumns());
  fmpz_mat_init(m2, A.numColumns(), A.numColumns());
  fmpq_mat_get_fmpz_mat_rowwise(m1, nullptr, A.fmpq_mat());
  // fmpz_mat_print_pretty(m1);
  size_t nullity = fmpz_mat_nullspace(m2, m1);
  // now copy the first 'nullity' columns into result_nullspace
  result_nullspace.resize(A.numColumns(), nullity);
  for (size_t c = 0; c < nullity; c++)
    for (size_t r = 0; r < A.numColumns(); r++)
      fmpz_set(fmpq_numref(&result_nullspace.entry(r, c)),
               fmpz_mat_entry(m2, r, c));
  fmpz_mat_clear(m1);
  fmpz_mat_clear(m2);
  return nullity;
}

References DMat< M2::ARingQQFlint >::entry(), DMat< M2::ARingQQFlint >::fmpq_mat(), DMat< M2::ARingQQFlint >::numColumns(), DMat< M2::ARingQQFlint >::numRows(), and DMat< M2::ARingQQFlint >::resize().