Robin boundary conditions for ParticleFlux

[RemDelaporteMathurin]

Proposed changes

This closes #749.

Uage:

import festim as F
import numpy as np
import ufl


my_model = F.HydrogenTransportProblem()
my_model.mesh = F.Mesh1D(vertices=np.linspace(0, 1, 1000))
my_mat = F.Material(name="mat", D_0=1, E_D=0)
vol = F.VolumeSubdomain1D(id=1, borders=[0, 1], material=my_mat)
left = F.SurfaceSubdomain1D(id=1, x=0)
right = F.SurfaceSubdomain1D(id=2, x=1)

my_model.subdomains = [vol, left, right]

H = F.Species("H")
D = F.Species("D")
my_model.species = [H, D]

my_model.temperature = 500

recomb_flux = F.SurfaceReactionBC(
    reactant=[H, H],
    gas_pressure=0,
)

my_model.boundary_conditions = [
    F.DirichletBC(subdomain=left, value=10, species=H),
    F.ParticleFluxBC(
        subdomain=right,
        value=lambda c1, T: -0.01 * ufl.exp(-0 / F.k_B / T) * c1**2,
        species=H,
        species_dependent_value={"c1": H},
    ),
]

my_model.exports = [F.XDMFExport("test.xdmf", H)]

my_model.settings = F.Settings(atol=1e-10, rtol=1e-10, final_time=10, transient=True)

my_model.settings.stepsize = 0.1

my_model.initialise()
my_model.run()

Merge #750 before this.

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code refactoring
• Documentation Update (if none of the other choices apply)
• New tests

Checklist

• Black formatted
• Unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
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[codecov]

Codecov Report

Attention: Patch coverage is 95.45455% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 98.31%. Comparing base (f57b263) to head (d47c76e).

❗ Current head d47c76e differs from pull request most recent head 1e9c502. Consider uploading reports for the commit 1e9c502 to get more accurate results

Files	Patch %	Lines
festim/boundary_conditions/flux_bc.py	95.45%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           fenicsx     #752      +/-   ##
===========================================
- Coverage    98.42%   98.31%   -0.11%     
===========================================
  Files           28       28              
  Lines         1519     1540      +21     
===========================================
+ Hits          1495     1514      +19     
- Misses          24       26       +2     

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[jhdark]

Just a general comment on the create_value_fenics,, otherwise looks good

[jhdark]

Is it worth adding some extra logic in here to make sure 1. A species object is given 2. the arguments are unique and users don't give t, x or T 3. The species given is mobile.

Not sure if this is overkill or not

I gave a partial example of this in #746

[RemDelaporteMathurin]

I would hold this off for now as it's applicable to all paticle fluxes