vibeflow-fenics

name	vibeflow-fenics
description	Use when preparing, running, debugging, validating, or developing VibeFlow/VibeCAE FEniCS or FEniCSx finite-element PDE workflows, including Python weak forms, dolfinx/dolfin environments, mesh and boundary-tag handoff, solver setup, post-processing, reusable PDE modules, and traceability to 0-caseDict/caseDict.

VibeFlow FEniCS

This skill is responsible for integrating FEniCS/FEniCSx into VibeCAE as a Python-driven FEM/PDE backend.

• Usage mode: generate runnable Python FEM solver scripts from caseDict.
• Development mode: develop reusable weak forms, boundary mappings, material models, solver wrappers, or post-processing modules.

When to Use

• The current backend is FEniCS or FEniCSx.
• A PDE weak form, research FEM model, multiphysics prototype, or custom variational form needs to be implemented quickly.
• dolfinx, dolfin, ufl, basix, ffcx, or MPI/PETSc issues need to be handled.
• Gmsh/XDMF/mesh tags need to be mapped into a Python FEM script.

First Decide: Usage Mode or Development Mode

• Implementing the PDE/FEM solver script for the current case: use usage mode.
• Writing reusable weak-form libraries, material models, boundary-condition generators, or solver adapters: use development mode.
• Python packages cannot be imported: switch to vibeflow-toolchain.
• Mesh tags or dimensions are incorrect: switch to vibeflow-mesh.

What to Read First

• 0-caseDict/caseDict
• references/fenics-playbook.md
• references/fenics-practical-tips.md: software knowledge base, key concepts, failure interpretation, and adapter design points.
• XDMF, MSH, VTU, and mesh-tag files in B-mesh/
• Existing scripts in C-run/fenics/ and post-processing under D-post/

Inputs

• Unified physical description, materials, boundaries, initial conditions, and numerical settings
• FEM mesh and boundary tags
• Python environment and FEniCS/FEniCSx packages

Outputs

• C-run/fenics/case-1/solve.py
• C-run/fenics/case-1/mesh.xdmf and tag files
• C-run/fenics/case-1/results/
• Post-processing scripts under D-post/fenics/
• Solver logs and error/convergence records

Recommended Structure

C-run/fenics/case-1/
├── solve.py
├── inputs/
├── mesh/
├── results/
└── logs/

Usage Mode Workflow

1. Confirm the backend and FEniCS version: prefer FEniCSx/dolfinx; legacy dolfin may be used for older projects.
2. Read the PDE type, weak-form variables, materials, boundaries, and target quantities from caseDict.
3. Check mesh dimension, element type, cell tags, and facet tags.
4. Generate solve.py, keeping parameters centralized and paths relative to the case.
5. Run import checks and a minimal solve.
6. Output XDMF/VTK/CSV/JSON results.
7. Write run status, error norms, residuals, or target quantities back to caseDict.

Development Mode Workflow

1. Define the development target: weak-form library, material model, boundary generator, mesh conversion, PETSc solver configuration, or post-processing.
2. Write a minimal manufactured solution or benchmark first.
3. Split UFL forms, function spaces, boundary tags, and solver parameters into small functions.
4. Do not mix FEniCSx and legacy FEniCS APIs.
5. Under MPI, do not rely on single-process file-writing assumptions.
6. Record versions, dependencies, commands, and validation results.

Core Rules

• The FEniCS skill is not responsible for CAD modeling; geometry and mesh are provided by the geometry/mesh skills.
• caseDict is the source of truth for physical and numerical intent; the Python script is the backend implementation.
• Mesh tag names or IDs must be traceable to the regions/boundaries in caseDict.
• Solver convergence, errors, and unit assumptions must be recorded.
• Do not treat a notebook as the only reproducible run entry point; a script entry point is required.

Validation

• import dolfinx or import dolfin succeeds.
• Mesh and tags are readable.
• The minimal solve completes.
• Result files exist and can be read by post-processing.
• For a benchmark or manufactured solution, an error check or physical-consistency check exists.

Fallback Rules

• Unclear PDE/boundaries: return to vibeflow-case-dict
• Python/FEniCS environment unavailable: return to vibeflow-toolchain
• Mesh/tag problems: return to vibeflow-mesh
• Post-processing: switch to vibeflow-postprocess