[wangguanyao4-netizen]

This refactors the C++ hyperelasticity demo into a small set of reusable functions while preserving the numerical formulation and output.

Changes

• isolate mesh construction;
• isolate finite-element space construction;
• isolate the prescribed rotation field;
• isolate the two Dirichlet boundary conditions; and
• keep main responsible only for PETSc/logging lifecycle while solve_hyperelasticity owns the simulation.

The generated UFL forms and solver callbacks are unchanged. The resulting layout gives users a concrete pattern for separating setup, boundary data, solving, and output in a larger nonlinear mechanics program.

Validation

• clang-format --dry-run --Werror cpp/demo/hyperelasticity/main.cpp
• git diff --check

A full demo build/run was not run because this environment does not have CMake or the PETSc/DOLFINx build dependencies installed.

[schnellerhase]

Check your git config and rewrite the commit.

[schnellerhase]

Thanks, this reads way better.

This does not resolve #3076 (please remove the autoclose statement from the PR description).

If approved by others this could be extended in a similar manner to other demos (in future PRs), i.e. breaking out mesh generation, definition of functions and/or BCs, and post processing.