[aspect-devel] Problem with active tracers & compositional fields

[FELIPE ORELLANA ROVIROSA]

 Hi all,

       I am implementing a 3D model with one layer of compositional fields,
I want the convecting system to advect active tracers (they have a density
differential).

       The model seems to have correct syntax, as it starts to run. But it
fails, it fails by segmentation fault: The last liens of the log file state
that there some cells and all of their neighbors do not contain any
particles, and that makes the interpolation to crash.

      But, I have been increasing the number of tracer particles, all the
way up to 10^5. I have plotted them, and they would be waaay more than
enough to fill all the cells of the model, at least in its early stages.

  what is going on here?

  I am pasting the pertinent lines of my prm file:

subsection Postprocess
  set List of postprocessors = visualization, temperature statistics,
velocity statistics, composition statistics, tracers #,particle count
statistics, dynamic topography

#  subsection Dynamic Topography
#    set Density above = 1000
#  end

  subsection Visualization
 #   set List of output variables = dynamic topography
    set List of output variables = density
    set Time between graphical output = 3.1558e14 # 10 Ma
    set Output format = vtu
    set Number of grouped files = 1

#   subsection Dynamic Topography
#      set Density above = 1000
#   end

  end #end Visualization

  subsection Tracers
    set Number of tracers = 10000
    set List of tracer properties = initial position, initial composition,
velocity, pT path
    set Interpolation scheme = cell average
    set Update ghost particles = true
    set Time between data output = 3.1558e14
    set Data output format = vtu
    set Particle generator name = ascii file
#    set Number of grouped files = 1
 #
    subsection Generator
      subsection Ascii file
        set Data directory = ./
        set Data file name = MyTracers_100k_lower.txt
      end
    end

  end

end #end Postprocess

subsection Compositional fields
  set Number of fields = 1
  set Names of fields = lower  #, upper
  set Compositional field methods = particles #, particles
  set Mapped particle properties = lower:initial lower #, upper:initial
upper
end

This is a fraction of the output log:

Number of active cells: 4,096 (on 5 levels)
Number of degrees of freedom: 184,598 (107,811+4,913+35,937+35,937)

*** Timestep 0:  t=0 seconds
   Solving temperature system... 0 iterations.
[compute-0-3:29728] *** Process received signal ***
[compute-0-3:29728] Signal: Segmentation fault (11)
[compute-0-3:29728] Signal code: Address not mapped (1)
[compute-0-3:29728] Failing at address: 0xffffffff000186a0
[compute-0-4:28813] *** Process received signal ***
[compute-0-25:06630] *** Process received signal ***
[compute-0-25:06630] Signal: Segmentation fault (11)
...

...
The violated condition was:
    non_empty_neighbors != 0
The name and call sequence of the exception was:
    ExcMessage("A cell and all of its neighbors do not contain any
particles. " "The 'cell average' interpolation scheme does not support this
case.")
Additional Information:
A cell and all of its neighbors do not contain any particles. The 'cell
average' interpolation scheme does not support this case.
--------------------------------------------------------

Aborting!
##################
cheers,
Felipe
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