Problem applying pressure based boundary condition using ZouHe

[SoumyaShouvik]

If I want to implement inlet or outlet boundary condition to a specific pressure using ZouHe, it shows a TypeError : mul got incompatible shapes for broadcasting: (998,), (9,). I used nx= 1400, ny= 1000. I tried to apply a specific pressure in left vertical inlet wall ( x=0, y=0:1000 ) . Same problem arrives if I want to apply a specific pressure in right outlet boundary.

Outflow BC

outlet = self.boundingBoxIndices['right']
rho_outlet = np.ones(outlet.shape[0], dtype=self.precisionPolicy.compute_dtype)
self.BCs.append(ZouHe(tuple(outlet.T), self.gridInfo, self.precisionPolicy, 'pressure', rho_outlet))

**** Simulation Parameters for Cylinder ****
Parameter | Value

            Omega | 0.5518611517342236
 Grid Points in X | 1400
 Grid Points in Y | 1000
 Grid Points in Z | 0
   Dimensionality | 2
 Precision Policy | f64/f64
     Lattice Type | D2Q9
  Checkpoint Rate | 0

Checkpoint Directory | ./checkpoints
Downsampling Factor | 1
Print Info Rate | 200
I/O Rate | 100
Compute MLUPS | False
Restore Checkpoint | False
Backend | gpu
Number of Devices | 1
Volumetric Ratio of Solid : 0.502656
Time to create the grid mask: 0.3005838394165039
Time to create the local masks and normal arrays: 11.985322952270508
WARNING: Default initial conditions assumed: density = 1, velocity = 0
To set explicit initial density and velocity, use self.initialize_macroscopic_fields.
jax.errors.SimplifiedTraceback: For simplicity, JAX has removed its internal frames from the traceback of the following exception. Set JAX_TRACEBACK_FILTERING=off to include these.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/mnt/c/RunCodeHere/Projects/XLB/Permeability02_benchmark.py", line 297, in
sim.run(t_max)
File "/mnt/c/RunCodeHere/Projects/XLB/src/base.py", line 905, in run
f, fstar = self.step(f, timestep, return_fpost=self.returnFpost)
File "/mnt/c/RunCodeHere/Projects/XLB/src/base.py", line 841, in step
f_poststreaming = self.apply_bc(f_poststreaming, f_postcollision, timestep, "PostStreaming")
File "/mnt/c/RunCodeHere/Projects/XLB/src/base.py", line 804, in apply_bc
fout = fout.at[bc.indices].set(bc.apply(fout, fin))
File "/mnt/c/RunCodeHere/Projects/XLB/src/boundary_conditions.py", line 781, in apply
feq = self.calculate_equilibrium(fout)
File "/mnt/c/RunCodeHere/Projects/XLB/src/boundary_conditions.py", line 738, in calculate_equilibrium
feq = self.equilibrium(rho, vel)
File "/mnt/c/RunCodeHere/Projects/XLB/src/boundary_conditions.py", line 285, in equilibrium
feq = rho * self.lattice.w * (1.0 + 1.0 * cu + 0.5 * cu**2 - usqr)
File "/home/shouvik/anaconda3/lib/python3.9/site-packages/jax/src/numpy/array_methods.py", line 743, in op
return getattr(self.aval, f"{name}")(self, *args)
File "/home/shouvik/anaconda3/lib/python3.9/site-packages/jax/_src/numpy/array_methods.py", line 271, in deferring_binary_op
return binary_op(*args)
File "/home/shouvik/anaconda3/lib/python3.9/site-packages/jax/src/numpy/ufuncs.py", line 99, in fn
return lax_fn(x1, x2) if x1.dtype != np.bool else bool_lax_fn(x1, x2)
TypeError: mul got incompatible shapes for broadcasting: (998,), (9,).

[hsalehipour]

Hi @SoumyaShouvik. Thanks for raising this issue which was indeed a minor bug in our ZouHe implementation. I just fixed it and you can pull again. Please make sure to use
rho_outlet = np.ones((outlet.shape[0], 1), dtype=self.precisionPolicy.compute_dtype)
instead of:
rho_outlet = np.ones(outlet.shape[0], dtype=self.precisionPolicy.compute_dtype)