app_a_file_listing.md

Appendix A: File Listing

Complete File Manifest

Root

File	Description
README.md	Project overview and quick start.
LICENSE	MIT licence.

feaopt/ — Core Package

File	Description
__init__.py	Package initialisation; exports all public classes and functions.
structure_geometry.py	StructureGeometry class — topology, material properties, DOF mappings.
element_matrices.py	ElementMatrices class — stiffness and transformation matrix cache.
analysis_state.py	AnalysisState class — displacement, force, and residual vectors.
fea_analysis.py	FEAAnalysis class — linear and Newton–Raphson solvers.
load_case.py	LoadCase class — nodal load definition and scaling.
structure_plotter.py	StructurePlotter class and batch drawing functions — visualisation utilities.
optimize_thickness.py	optimize_thickness function — stress-ratio thickness optimiser.
subdivide_truss.py	subdivide_truss function — split truss members into sub-elements.
importers.py	import_csv_curve and import_igs_curve — geometry import from CSV and IGES files.
export_profile.py	export_profile — rasterise, trace, and export boundary profiles.

examples/ — Demos

File	Description
demo_beam.py	Curved beam import from IGES, FEA, optimisation, and profile export.
demo_truss.py	Warren truss subdivision, optimisation, and profile export with plotting.

profiles/ — Output (auto-created)

File	Description
*.txt	Exported spline point files for SolidWorks CAD import.
*.npz	NumPy data archives for post-processing.

docs/ — Documentation

File	Description
Home.md	Wiki home page with links to all chapters.
ch1_introduction.md	Introduction, installation, project layout.
ch2_theory.md	Element formulation, solvers, stress recovery, optimisation theory.
ch3_api_reference.md	Full API documentation for all public classes and functions.
ch4_examples.md	Worked examples: curved beam, truss, and minimal custom problem.
ch5_export.md	Profile export pipeline: rasterisation through SolidWorks import.
app_a_file_listing.md	This file listing and error reference.

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Dependencies

Package	Version	Required	Used for
NumPy	≥ 1.20	Yes	Array operations, linear algebra, vectorised element computations.
SciPy	≥ 1.7	Yes	Sparse matrix assembly (csr_matrix), sparse solves (spsolve), interpolation (interp1d).
matplotlib	≥ 3.4	No (recommended)	All visualisation: beam rendering, stress plots, diagnostic figures.
scikit-image	≥ 0.19	For export only	Rasterisation (draw.polygon), morphology (closing, remove_small_objects), contour tracing (find_contours).

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Error and Warning Reference

The Python port uses standard Python exceptions (ValueError, IndexError, ImportError) and warnings.warn rather than MATLAB-style error IDs. The table below lists the key error conditions and where they originate.

Exceptions

Exception	Module	Condition
ValueError	structure_geometry	Connectivity references invalid node.
ValueError	structure_geometry	Zero-length element detected.
ValueError	structure_geometry	Non-positive material or section property.
ValueError	structure_geometry	Constraint references invalid node or DOF.
ValueError	structure_geometry	Thickness not positive (in update_thickness).
ValueError	analysis_state	Free-DOF vector size mismatch.
ValueError	load_case	Node ID out of range.
ValueError	optimize_thickness	No non-rigid elements to optimise.
ValueError	export_profile	No elements remain after filtering.
ValueError	importers	Fewer than 2 points in CSV file.
ValueError	importers	No supported entities in IGES file.
ValueError	importers	Could not chain IGES entities.
IndexError	structure_geometry	Element or node ID out of range.
ImportError	export_profile	scikit-image not installed.
ImportError	structure_plotter	matplotlib not installed.

Warnings

Warning	Module	Condition
No constraints applied	structure_geometry	Structure has no boundary conditions — rigid-body motion possible.
Non-convergence	fea_analysis	Newton–Raphson did not converge within iteration limit.
NaN/Inf in increment	fea_analysis	Numerical failure in displacement increment.
Negative load factor	load_case	Negative λ applied (may be intentional).
Chain gap	importers	Gap detected between IGES entities during chaining.
Incomplete chain	importers	Could not chain all IGES entities.