compare_res_pairs()

int res_comp::compare_res_pairs ( res_pair * f, res_pair * g ) const

private

Definition at line 318 of file res-a1.cpp.

{
  exponents_t EXP1, EXP2;
  int cmp, df, dg, i;
  //  if (f->compare_num < g->compare_num) return 1;
  //  if (f->compare_num > g->compare_num) return -1;
  // MES: what to do if we obtain equality? Here is one way:
  switch (compare_type)
    {
      case 1:
        // Compare using descending lexicographic order
        // on the usual set of variables
        EXP1 = ALLOCATE_EXPONENTS(exp_size);
        EXP2 = ALLOCATE_EXPONENTS(exp_size);
        M->to_expvector(f->base_monom, EXP1);
        M->to_expvector(g->base_monom, EXP2);
        for (i = 0; i < M->n_vars(); i++)
          {
            if (EXP1[i] < EXP2[i]) return -1;
            if (EXP1[i] > EXP2[i]) return 1;
          }
        return 0;
      case 2:
        // Compare using ascending lexicographic order
        // on the usual set of variables
        EXP1 = ALLOCATE_EXPONENTS(exp_size);
        EXP2 = ALLOCATE_EXPONENTS(exp_size);
        M->to_expvector(f->base_monom, EXP1);
        M->to_expvector(g->base_monom, EXP2);
        for (i = 0; i < M->n_vars(); i++)
          {
            if (EXP1[i] < EXP2[i]) return 1;
            if (EXP1[i] > EXP2[i]) return -1;
          }
        return 0;
      case 3:
        // Compare using descending lexicographic order
        // on the reversed set of variables
        EXP1 = ALLOCATE_EXPONENTS(exp_size);
        EXP2 = ALLOCATE_EXPONENTS(exp_size);
        M->to_expvector(f->base_monom, EXP1);
        M->to_expvector(g->base_monom, EXP2);
        for (i = M->n_vars() - 1; i >= 0; i--)
          {
            if (EXP1[i] < EXP2[i]) return -1;
            if (EXP1[i] > EXP2[i]) return 1;
          }
        return 0;
      case 4:
        // Compare using ascending lexicographic order
        // on the reversed set of variables
        EXP1 = ALLOCATE_EXPONENTS(exp_size);
        EXP2 = ALLOCATE_EXPONENTS(exp_size);
        M->to_expvector(f->base_monom, EXP1);
        M->to_expvector(g->base_monom, EXP2);
        for (i = M->n_vars() - 1; i >= 0; i--)
          {
            if (EXP1[i] < EXP2[i]) return 1;
            if (EXP1[i] > EXP2[i]) return -1;
          }
        return 0;
      case 5:
        // The original method, but with degree added, since
        // the new skeleton code doesn't just sort elements of
        // the same degree.
        df = degree(f);
        dg = degree(g);
        if (df > dg) return -1;
        if (df < dg) return 1;
        cmp = M->compare(f->base_monom, g->base_monom);
        if (cmp != 0) return cmp;
        cmp = f->first->compare_num - g->first->compare_num;
        if (cmp < 0) return 1;
        if (cmp > 0) return -1;
        return 0;
      default:
        cmp = M->compare(f->base_monom, g->base_monom);
        if (cmp != 0) return cmp;
        cmp = f->first->compare_num - g->first->compare_num;
        if (cmp < 0) return 1;
        if (cmp > 0) return -1;
        return 0;
    }
  return 0;
}

References ALLOCATE_EXPONENTS, res_pair::base_monom, res_pair::compare_num, compare_type, degree(), exp_size, res_pair::first, and M.

Referenced by merge_res_pairs().