--> Using symmetry version of the code: 
      [-psi, -tilt, -rot] is applied to the references, thereby 
      tilt and psi are sampled on an hexagonal lattice, 
      and rot is sampled linearly 
      Note that --dont_limit_psirange option is not allowed.... 
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 | Read more about this program in the following publication:    |
 |  Scheres ea.  (2009) Structure, 17, 1563-1572                 |
 |                                                               |
 |   *** Please cite it if this program is of use to you! ***    |
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--> Maximum-likelihood multi-reference refinement 
  Input images            : input/Ml_tomo/short.xmd (3)
  Reference image(s)      : input/Ml_tomo/vir_norm.spi
  Output rootname         : tmpLink/xmipp_mpi_ml_tomo/test1/iter22
  Angular sampling rate   : 5 degrees
  Symmetry group          : i3
  Stopping criterium      : 5e-05
  initial sigma noise     : 1
  initial sigma offset    : 0.32
  Maximum resolution      : 0.45 pix^-1
  Use images of size      : 16
  Missing data info       : input/Ml_tomo/wedgenew.doc
  Missing data treatment  : conventional division 
  -> Use constrained correlation coefficient instead of ML-imputation approach.
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  Multi-reference refinement:  iteration 1 of 1