Description

Summary

This PR fixes a bug where the space- and time-dependent temperature was not updated when used in DirichletBCs.

Related Issues

Related to #1060 and #1007

Motivation and Context

Following #1060 we added the .sub_T attribute to subdomains in order to work around FEniCS/dolfinx#3207

However, we don't update in time this .sub_T if the temperature is time dependent.

Consider the following MWE (run on main) where the BC is $c = 2 T$ on the boundary:

from mpi4py import MPI
import dolfinx
import festim as F

my_model = F.HydrogenTransportProblemDiscontinuous()

n = 8
mesh = dolfinx.mesh.create_unit_square(MPI.COMM_WORLD, n, n)
my_model.mesh = F.Mesh(mesh)

surface_1 = F.SurfaceSubdomain(id=1)

material_1 = F.Material(D_0=1, E_D=0, name="material_1")
volume_1 = F.VolumeSubdomain(id=2, material=material_1)

my_model.subdomains = [surface_1, volume_1]

H = F.Species(name="H", subdomains=my_model.volume_subdomains)
my_model.species = [H]


my_model.boundary_conditions = [
    F.FixedConcentrationBC(species=H, subdomain=surface_1, value=lambda T: 2 * T)
]

my_model.temperature = lambda t, x: 1 + x[0] + x[1] + t

my_model.settings = F.Settings(final_time=1, atol=1e-9, rtol=1e-9, stepsize=0.1)

avg_surf = F.AverageSurface(field=H, surface=surface_1)
my_model.exports = [avg_surf]

my_model.initialise()
my_model.run()

print(avg_surf.data)

The average surface concentration should increase in time but:

[4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0]

Type of Change

• 🐛 Bug fix (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 (no functional changes, no API changes)
• 📝 Documentation update
• ✅ Test update (adding missing tests or correcting existing tests)
• 🔧 Build/CI configuration change

Testing

• All existing tests pass locally (pytest)
• I have added new tests that prove my fix is effective or that my feature works

Code Quality Checklist

• My code follows the code style of this project (Ruff formatted: ruff format .)
• My code passes linting checks (ruff check .)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas

Documentation

• I have updated the documentation accordingly (if applicable)
• I have added docstrings to new functions/classes following the project conventions

Breaking Changes

Screenshots/Examples

Additional Notes