code: def _dm_rref_den_FF(M):
      """Compute RREF using fraction-free Gauss-Jordan elimination."""
      if M.rep.fmt == "sparse":
          return _dm_rref_den_FF_sparse(M)
      else:
          return _dm_rref_den_FF_dense(M)
  
file_path: sympy/sympy/polys/matrices/rref.py
imports: from sympy.polys.domains import ZZ
  from sympy.polys.matrices.sdm import SDM, sdm_irref, sdm_rref_den
  from sympy.polys.matrices.ddm import DDM
  from sympy.polys.matrices.dense import ddm_irref, ddm_irref_den
label_desc: Use image node_id 5 for calling a global function with example usage: _dm_rref_den_FF(M) and returns: _dm_rref_den_FF_sparse, _dm_rref_den_FF_dense