Can we output picard iteration process with postprocessors? new_row_detection_columns = all seems useless?

[Wang-Yihu]

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Question

When I read the code https://github.com/idaholab/moose/blob/next/tutorials/tutorial02_multiapps/step03_coupling/02_parent_picard.i
I want to see the process for picard iterations
So I add

[Outputs]
  exodus = true
  [output_average_u]
    type = CSV
    execute_on = 'MULTIAPP_FIXED_POINT_END'
    new_row_detection_columns = all
  []
[]

and

[Postprocessors]
  [average_u]
    type = ElementAverageValue
    variable = u
    execute_on = 'MULTIAPP_FIXED_POINT_END'
    outputs = 'output_average_u'
  []
[]

but the result seems that no picard iterations are output in the csv. The result is still with timestep

[GiudGiud]

Hello

MULTIAPP_FIXED_POINT_END

This is the equivalent of time step end, but only one per fixed point loop, rather than once at the end of the time step inside each fixed point iteration

Can we output picard iteration process with postprocessors?

Essentially not without modifying MOOSE at this time. We need to use the picard iteration index to differentiate the output (writing to a different files for example), and that is not done yet

[Wang-Yihu]

All right. When I set execute_on = 'MULTIAPP_FIXED_POINT_END' for exodus, I find that the file size is bigger than that with 'TIMESTEP_END'. I can read it with Python meshio netCDF4 pyvista, but with paraview, it can only output one contour for one time step, even there are several results for picard iterations for one step...