Full toolchain port. Numerical equivalence verified against MATLAB:
- main_mode_sweep.jl: every mode's final state matches MATLAB to 3-4 dp
- reach_operation.jl: per-halfspace margins match MATLAB exactly
- barrier_lyapunov.jl: per-halfspace bounds match (best Qbar from sweep
yields max|dT_c| = 33.228 K either side)
- barrier_compare_OL_CL.jl: OL gamma 1.038e13, CL gamma 1.848e4
matching the MATLAB result; LQR helps by ~20,000x on every halfspace.
Phase summary:
Phase 1: pke_solver.jl, plot_pke_results.jl (Plots.jl), main_mode_sweep.jl
Phase 2: reach_linear.jl, reach_operation.jl, barrier_lyapunov.jl,
barrier_compare_OL_CL.jl, load_predicates.jl
Phase 3 (this commit): delete plant-model/ entirely, delete reach
code from reachability/ keeping predicates.json + docs,
git mv julia-port/ -> code/, update root README + CLAUDE,
write code/CLAUDE.md and code/README.md, update reach
README + WALKTHROUGH file paths, journal preamble note
that pre-port entries reference MATLAB paths.
Why now: prompt-neutron stiffness in nonlinear reach made it clear we
need TMJets, which is Julia. Already had the Julia plant model
working and matching MATLAB. Two languages = two sources of truth =
two places to drift. One language, one truth.
Manifest.toml gitignored. .mat results gitignored.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Three caveats surfaced during walkthrough lived only in the
conversation transcript before this commit. Now they live where
future agents and future-me will actually see them:
- reach_operation.m and reachability/README.md state prominently that
the current reach tube is an over-approximation of the LINEAR
model, not a sound tube for the nonlinear plant. Thesis-blocking
for a real safety claim. Upgrade paths documented.
- ctrl_heatup.m header and plant-model/CLAUDE.md note that the
feedback-linearization u_ff assumes exact alpha_f, alpha_c. Real
plants drift (burnup ~20%, boron ~10x, xenon). Robust treatment =
parametric reach with alpha as an interval.
- ctrl_heatup.m header and plant-model/CLAUDE.md note that sat() is
formally a 3-mode piecewise-affine sub-system. Operation-mode LQR
is dormant (trivially); heatup will need either a dormancy proof
or explicit hybrid modeling.
README.md top-level now has a run-commands table for the reach
artifacts and a pointer to the soundness status.
Hacker-Split: raise caveats from transcript to artifact so the work
is actually reviewable by people who weren't in the room.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Stand up reachability/ with a hand-rolled zonotope propagator for
linear closed-loop systems (reach_linear.m: axis-aligned box hull,
augmented-matrix integration for the disturbance convolution). Use it
in reach_operation.m to discharge the operation-mode safety obligation:
from a +/-0.1 K box on T_avg, under Q_sg in [85%, 100%]*P0, LQR keeps
T_c within 0.03 K of setpoint over 600 s. Safety band is +/-5 K, so
the obligation is satisfied with five orders of margin.
barrier_lyapunov.m attempts the analytic counterpart via a weighted
Lyapunov function. Sweeping the Qbar(T_c) weight, the best quadratic
barrier allows ~33 K deviation on the gamma level set — still outside
the 5 K safety band. This is a fundamental limitation of quadratic
barriers for anisotropic safety specs (thin-slab safe set in a
precursor-heavy state space). Documented in the file: next step for a
tight analytic certificate is SOS polynomial or polytopic barrier,
which need solvers we don't have locally yet.
reach_linear.m started out with a halfwidth-propagation bug (signed
A_step instead of |A_step|); fixed before commit after noticing the
reach envelope exactly matched the initial box on T_c.
Figures saved to docs/figures/. .mat result files gitignored — they
are regenerated in <1s.
Hacker-Split: first end-to-end per-mode reachability artifact.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
