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[Bruno Chareyre <1260213@xxxxxxxxxxxxxxxxxx>]

Not a bug, although the documentation could be more explicit.

Docstring:
    imposePressure( (FlowEngine)arg1, (Vector3)pos, (float)p) -> int :                                                                                                      
        Impose pressure in cell of location 'pos'. The index of the condition is returned

Docstring:
    getCellFlux( (FlowEngine)arg1, (int)cond) -> float :                                                                                                              
        Get influx in cell associated to an imposed P (indexed using 'cond').

imposePressure() returns an index, this index can be used to get the associated flux.
It doesn't matter if the element containing the middle point is element 127 or 1333 (the values you get with getCell()). 
The first point where pressure is imposed will get index 0, the next one will be 1, etc. In other words, the getCell function is useless in your case.

There is a good reason for that.The mesh is changing with time (as soon
as deformation occures), so that the index of the element containing the
middle point is changing all the time. It is something you don't have to
worry about if each imposed pressure is assigned a static index.

A correct sequence is like this:

middleCellCond = flow.imposePressure(Vector3(xDim/2,yDim/2,zDim/2),porePressure) 
O.run(1,1)
influx = flow.getCellFlux(middleCellCond)


** Changed in: yade
       Status: New => Invalid

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https://bugs.launchpad.net/bugs/1260213

Title:
  error in FlowEngine with imposed pressure and getCellFlux()

Status in Yet Another Dynamic Engine:
  Invalid

Bug description:
  Hi,

  I want to increase pore pressure in a PFV cell in the middle of my model containing loose granular material (sand).
  So I did:
  #################

  porePressure = 5000000

  middleCell = flow.getCell(Vector3(xDim/2,yDim/2,zDim/2)) # [1]

  print 'increased pore pressure at ',Vector3(xDim/2,yDim/2,zDim/2), '
  to ',porePressure

  flow.imposePressure(Vector3(xDim/2,yDim/2,zDim/2),porePressure) # [2]

  #I want to see which velocity corresponds to this porePressure:

  vel_fluid = flow.getCellFlux(middleCell) # [3]

  #################

  This error messages occured:

  Triangulation does not exist. Waht did you do?!
  increased pore pressure at  Vector3(0,001,0,001,0,0015)  to  5000000
  Traceback (most recent call last):
    File "<string>", line 1, in <module>
    File "scripts/definitions-final.py", line 78, in writeData
      vel_fluid = flow.getCellFlux(middleCell)
  OverflowError: can't convert negative value to unsigned

  [1] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.FlowEngine.getCell
  [2] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.FlowEngine.imposePressure
  [3] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.FlowEngine.getCellFlux

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