forked from 1b-agent/fieldcraft-upstream
* fem: wedge6 element (triangle × interval, 3 × 2 points), patch and cantilever tests Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * solver: reference points, kinematic and distributing couplings, moments by constraint elimination Coupled reference points get six degrees of freedom; kinematic couplings are rigid links, distributing couplings least-squares interpolation constraints. Every constraint row and prescribed value is eliminated master-slave (Abel-Shephard pivot choice), so the reduced matrix stays SPD; no coupling gives the old elimination bit for bit. Verified: rigid motion of a coupled block, clamping through a point, distributing tension vs pressure, bending and tube torsion. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * engine: reference point results in solve.static and solve.probe Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * docs: couplings, moments and wedge6 in the solver docs, literature and roadmap Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * solver: simplify constraint elimination and reference point plumbing Rows combine by one sort; T_f transposed once; K and M reduced in one pass on a shared pattern; prescribed motion computed once; reference point loads and BCs go through Resolved like node ones (Mesh::label_dofs); one dof-direction rule; StepResult::locate for probes; dead Csr::restrict removed. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * solver: refuse oversized reductions before allocating them A held distributing coupling point makes a dense (3N)^2 block; estimate it from the constraint rows and refuse it against the factorization's memory budget with a clear message, before anything is built. Other reductions with dependents count their entries first (stopping at the budget) and reserve fallibly. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm --------- Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com> Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>