code: def par_relax_AX(i):
      
  
      global mp_X
      global mp_Xnr
      global mp_DX
      global mp_DXnr
      mp_Xnr[mp_grp[i]:mp_grp[i+1]] = mp_X[mp_grp[i]:mp_grp[i+1]]
      mp_DXnr[i] = mp_DX[i]
      if mp_rlx != 1.0:
          grpind = slice(mp_grp[i], mp_grp[i+1])
          mp_X[grpind] = mp_rlx * mp_X[grpind] + (1-mp_rlx)*mp_Y1[grpind]
          mp_DX[i] = mp_rlx*mp_DX[i] + (1-mp_rlx)*mp_Y0[i]
docs: Parallel implementation of relaxation if option ``RelaxParam`` !=
      1.0.