```Question #690803 on Yade changed:
```
Guilherme das Neves Seguro posted a new comment:
Hello mr Scholtès;

it is the same code I've shared in [1]. I'm having trouble in measuring
the permeability and I was concerned that it might be because of a wrong
setting the Pressure Condition.

The main code is shared in [2] (by now I corrected my mistake of making
it open to everyone!) and this current question is on this part of the
code:

PRESS=0.0
[...]
bottom=0

[then the code calls a secondary script and comes to]

### Flow Engine ###
flow=DFNFlowEngine(
isActivated=False
,useSolver=3  # (0: Gauss Seidel, 1: Taucs, 2: Pardiso, 3: CHOLMOD)
#,boundaryUseMaxMin=[0,0,0,0,0,0] # [left, right, bottom, top, back,
front]: False means boundary made with walls
,bndCondIsPressure = [0,0,bottom,0,0,0] #
bndCondIsPressure(=vector<bool>(6, false))
# bndCondIsPressure=[left, right,
bottom, top, back, front]
# ,bndCondValue=[0,0,0,0,PRESS,0]
,bndCondValue=[0,0,PRESS,0,0,0] # bndCondValue(=vector<double>(6,0))
,permeabilityFactor=pFactor
,viscosity=visc
,fluidBulkModulus=KFluid
### DFN related
,clampKValues=False
,jointsResidualAperture=slotAperture
)

[fluid injection occurs and after that I need to impose the pressure on
y axis as I asked. So I change the parameters to]

bottom = 1
PRESS  = 3e6

O.run(1,True)
# getBoundaryFlux get the total discharge [m3/s]
Qin  = flow.getBoundaryFlux(2)
Qout = flow.getBoundaryFlux(3)
# if Qout is the total discharge, we can compute k=Q*nu*Length/(Area*(Pout-Pin))
# if Qout is the flux, we can compute k=Q*nu*Length/(Pout-Pin) -> getFlux gives
total discharge -> Qout (m3/s)!
permeability = abs(Qout)*flow.viscosity*Y/(X*Z) # !!! if Pout=1, Pin=0
permeability2 = flow.averageVelocity()*flow.viscosity*Y # !!! if Pout=1, Pin=0
conductivity = permeability*DENS_FLUID*9.82/flow.viscosity # K=rho*g*k/nu
print "\n\nQin=",Qin,"\nQout=",Qout,"\nOBS: ARE THEY EQUAL? IF NOT => NO
FLOW!\n"
print "\n\nPermeability [m2]=",permeability,"\nHydraulic conductivity
[m/s]=",conductivity, '\n\nTHE END!\n'

rrLStPBemmjIBDlGO_ZVMupDyzDO5b?usp=sharing

Thank you very much for all your support, guys!

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