645f2d8d27
Singular-perturbation reduction of the PKE+T/H system: set dn/dt=0,
solve algebraically n = Λ·Σλ_i·C_i / (β-ρ). State drops 10 -> 9 (no
n), removes Λ⁻¹ stiffness. Validated against full state on the heatup
scenario:
t [s] |Δn|/n_full T_c err [K]
60 3.7e-5 4e-6
300 3.8e-4 1.9e-4
1200 1.0e-3 2.2e-3
3000 5.0e-4 7.2e-3
Maximum relative error 0.1% on n, peak 7 mK on temperatures over
50 minutes. PJ approximation is excellent for slow heatup transients
(sub-prompt-critical regime).
Files:
- code/src/pke_th_rhs_pj.jl: reduced 9-state RHS
- code/scripts/validate_pj.jl: side-by-side sim
- code/scripts/reach_heatup_pj.jl: TMJets reach with PJ model
(probing T = 60, 300, 1800, 5400 s)
App v2 (Pluto):
- §9b: live ingestion of reach_operation_result.mat with per-
halfspace margins computed from JSON-defined inv2_holds.
- §9c: 2D projection chooser (n, T_f, T_c, T_cold) with reach
tube envelope overlay.
- §9d: PJ heatup reach summary (placeholder until first run lands).
Journal:
- Added 2026-04-20-overnight-prompt-jump.tex with PJ derivation,
validation table, soundness ledger update. apass markers for
the in-progress reach results.
This commit captures state mid-run; next commit will add the
populated reach results once TMJets returns.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Lab Journal
___
,' `.
/ ___ \ n, C_i,
| ( UO2 ) | T_f, T_c, T_cold
\ ‾‾‾ / |
`.___,' v
||||| →→→→ [ controller ] →→→→ rods
|||||
‾‾‾‾‾‾‾‾‾‾‾‾‾ primary loop
___________
| SG | Q_sg(t) ∈ [Q_min, Q_max]
|____________|
The HAHACS invention log for the pwr-hybrid-3-demo preliminary
example. Each dated session gets an entry. The goal: a reader in 2030
should be able to rebuild the thesis work from this journal alone.
Structure
journal/
preamble.tex shared LaTeX setup (fonts, listings, callouts, macros)
journal.tex top-level aggregator (builds all entries into one PDF)
entries/ dated session entries, one file per session
YYYY-MM-DD-{topic-slug}.tex
figures/ journal-specific figures (referenced from entries)
README.md this file
Conventions
Filename
entries/YYYY-MM-DD-{topic-slug}.tex. One file per session. If a day has multiple distinct sessions, use time-of-day in the slug (e.g., 2026-04-20-morning-predicates.tex and 2026-04-20-evening-mega-session.tex).
Entry skeleton
\session{2026-04-17}{duration}{one-line summary}
\section{Session: ... (YYYY-MM-DD)}
\label{sec:YYYYMMDD}
\subsection*{Goal}
What I set out to do and why.
\subsection*{What landed}
...
\subsection*{Key decisions}
...
\subsection*{Dead ends}
...
\subsection*{Derivations}
...
\subsection*{Results}
...
\subsection*{Limitations recorded}
...
\subsection*{Open at close}
...
Entries compile standalone (each starts with \input{../preamble.tex} wrapped in a conditional so it only pulls preamble when not already loaded by journal.tex), or together via journal.tex.
Two entry styles
- A-style (deep / invention-log): full derivations, code commentary, dead-ends, embedded figures, terminal output where useful. Used for retroactive entries and sessions that land meaningful artifacts.
- B-style (narrative + pointers): end-of-session notes. Uses
\apass{...}callouts to flag spots that need a later A-pass.
Callout boxes
From preamble.tex:
| Environment | Use |
|---|---|
derivation |
Math derivations |
decision |
Design choices with rationale + alternatives |
deadend |
Paths that didn't work |
limitation |
Soundness gaps, known-approximate behavior |
Plus the inline \apass{text} marker for A-pass TODOs.
Code inclusion
\juliafile[options]{path/to/file.jl}— includes a Julia source file as a numbered listing.\matlabfile[...]{...}— for MATLAB sources.- Or inline with
lstlistingenvironment andlanguage=Juliafor snippets.
Always include the path as the listing caption so readers can find the file.
Figures
Figures live in ../docs/figures/ (shared with the thesis) or figures/ (journal-only). The preamble sets \graphicspath to check both.
Always include:
- A descriptive caption (what's on axes, what's being shown).
- A discussion in the surrounding prose — what the figure proves or illustrates. Figures without discussion are noise.
Terminal output
For a numerical result or an error that drove a decision, include the actual terminal text in a lstlisting block with style=terminal:
\begin{lstlisting}[style=terminal]
TMJets: 10583 reach-sets
T_c envelope: [274.45, 295.0] C
FAILED: AssertionError: radius must be nonnegative
\end{lstlisting}
Don't include full logs — only the lines that changed what you did next.
Build
cd journal
latexmk -pdf journal.tex # whole journal as one PDF
latexmk -pdf entries/2026-04-17-controllers-linear-reach.tex # one entry
Requires TeX Live with tcolorbox, listings, inconsolata, siunitx, cleveref, hyperref, fancyhdr. All in the standard distribution.
Not a replacement for
claude_memory/— short AI-context notes, Markdown, different audience.reachability/WALKTHROUGH.md— standalone doc summarizing current state of reach analysis.- Git commit messages — per-commit rationale for code changes.
The journal is the chronological narrative of the work. The others are snapshots, summaries, or pointers. They're all legitimate; they do different things.