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    <p>Dear Quantum Espresso community,</p>
    <p>I have a structure where the phonon calculation for a single
      irreducible q-point fails (it works for all other q-points),
      rendering the error:</p>
    <p><i>Error in routine set_irr_sym_new</i></p>
    <p><i>wrong representation</i></p>
    <p>I am using version 6.2.1.<br>
      <i></i></p>
    <p>I've seen that this problem has come up before but there wasn't
      always a working solution for it.</p>
    <p>I have tried increasing the threshold which sends the error in
      set_irr_sym.f90 as sometimes suggested. <br>
    </p>
    <p>I have also tried generating different random matrices (created
      by random_matrix_new()) by changing the random number generator
      seed, using uniformly distributed numbers</p>
    <p>and using normally distributed random numbers with different mean
      value and variance. Unfortunately, I always get the same error at
      this q-point. I also had no success with changing all</p>
    <p>atom positions slightly.</p>
    <p>I'd be thankful for any other suggestions.<br>
    </p>
    <p><br>
    </p>
    <p>Cheers,</p>
    <p>Noé Mascello</p>
    <p>ETH Zurich</p>
    <p><br>
    </p>
    <p>________________________________________</p>
    <p>scf input</p>
    <p>&CONTROL<br>
          calculation   = 'scf'<br>
          restart_mode  = 'from_scratch'<br>
          prefix        = 'P4ncc_00'<br>
          pseudo_dir    = '/pps'<br>
          outdir        = './'<br>
      /<br>
      &SYSTEM<br>
          ibrav       = 6<br>
          A           = 5.28231<br>
          B           = 5.28231<br>
          C           = 7.84336<br>
          cosAB       = 0<br>
          cosAC       = 0<br>
          cosBC       = 0<br>
          nat         = 16<br>
          ntyp        = 2<br>
          ecutwfc     = 90<br>
          occupations = 'smearing'<br>
          degauss     = 7.35d-4<br>
      <br>
      /<br>
      &ELECTRONS<br>
          conv_thr    = 1.0d-8<br>
          diagonalization = 'cg'<br>
      /<br>
      <br>
      ATOMIC_SPECIES<br>
      W 183.84 W_ONCV_PBE-1.1.upf<br>
      O 15.9994 O_ONCV_PBE-1.0.upf<br>
      <br>
      <br>
      ATOMIC_POSITIONS crystal<br>
           W 0.250000000         0.250000000         0.219699999<br>
           W 0.749999977         0.749999977         0.780300001<br>
           W 0.749999977         0.749999977         0.280300031<br>
           W 0.250000000         0.250000000         0.719699969<br>
           O 0.250000000         0.250000000         0.493539985<br>
           O 0.749999977         0.749999977         0.506460015<br>
           O 0.749999977         0.749999977         0.006460011<br>
           O 0.250000000         0.250000000         0.993540015<br>
           O 0.460340007         0.539659993         0.250000000<br>
           O 0.539659993         0.460340007         0.749999985<br>
           O 0.039660007         0.960340007         0.250000000<br>
           O 0.960340007         0.039659976         0.749999985<br>
           O 0.960340007         0.460340007         0.250000000<br>
           O 0.039659976         0.539659993         0.749999985<br>
           O 0.539659993         0.039660007         0.250000000<br>
           O 0.460340007         0.960340007         0.749999985<br>
      <br>
      K_POINTS automatic<br>
      8 8 6 0 0 0</p>
    <p>_______________________________<br>
    </p>
    <p>ph.x input (2nd q-point):</p>
    <p><br>
      &INPUTPH<br>
          prefix   = 'P4ncc_00'<br>
          outdir   = './q2'<br>
          fildyn   = 'P4ncc_00.dyn'<br>
          fildvscf = 'dvscf'<br>
          ldisp    = .true.<br>
          nq1      = 4<br>
          nq2      = 4<br>
          nq3      = 3<br>
          asr      = .true.<br>
          tr2_ph   = 1.0d-14<br>
          start_q = 2<br>
          last_q = 2<br>
          recover = .true.<br>
          search_sym = .false.<br>
      /<br>
      <br>
    </p>
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