Greg Pomerantz
0c4a1f9f60
- fix encoded-polyline decoder (zigzag: (n>>1) ^ -(n&1)) — caught by the OSRM integration tests (Boston clearance 5681km -> 38km) - OSRM client: routes[] JSON shape, overview=full for geometry, polyline+geojson support - local OSRM 26.4.1 built from source (no sudo): deps.sh (bzip2, lua 5.2 with readline stub, oneTBB, boost 1.84 via b2 + hand-rolled CMake config files, osmium-tool), setup-osrm.sh (merge PBFs -> extract -> partition -> customize -> serve :5000); v26 flag fixes - bench: tasks.osrm.json goldens; both backends 26/26 PASS and agree on all 5 optimized orders (Ladd->Cascade etc.) - README: profile deltas (Valhalla 332min vs OSRM 410min, same route shape), per-backend goldens, verified self-host status
141 lines
6.3 KiB
Markdown
141 lines
6.3 KiB
Markdown
# maps/router — route-aware planning primitives
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The Go backend for the "search along the route" capability
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([DESIGN.md](../DESIGN.md), "Driving trips" section). Everything the LLM
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would otherwise *guess* about a trip — route shape, travel times, detour
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costs — is computed here and returned with provenance.
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## What's in here
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```
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internal/geo/ dependency-free geodesy (haversine, point-to-line)
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internal/route/ Router interface + backends
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- valhalla.go: hosted/self-hosted Valhalla (works today;
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no geometry on the hosted instance → chord fallback)
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- osrm.go: local OSRM (full geometry; scripts/setup-osrm.sh)
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internal/plan/ the primitives:
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- stopcost.go: stop_cost = route(A,C via B) − route(A,C)
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- optimize.go: optimize_stops (exhaustive ≤10 stops, greedy above)
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- corridor.go: corridor = buffer band around the route
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cmd/routectl/ manual CLI: route | stopcost | optimize
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cmd/bench/ benchmark runner (bench/tasks.json)
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bench/tasks.json 5 real NE-corridor tasks with recorded goldens
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scripts/setup-osrm.sh self-host OSRM over the NH+MA+CT+NY extract
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```
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Zero third-party Go dependencies (stdlib only).
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## Try it (hosted Valhalla, no setup)
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```sh
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go run ./cmd/routectl route --from 44.054,-71.650 --to 40.729,-73.966
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# Lincoln NH → Queens NY: ~5h32m, 531 km, I-93/90/495/290 (NOT via Boston)
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go run ./cmd/routectl stopcost --from 44.054,-71.650 --to 40.729,-73.966 \
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--stop 42.2767,-71.806:60:cascade \
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--stop 43.507,-71.548:50:ladd \
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--stop 43.642,-71.156:120:mtmajor
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# cascade detour= 6 min (on the I-495 corridor)
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# ladd detour=17 min
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# mtmajor detour=80 min (off-corridor)
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go run ./cmd/routectl optimize --from 44.054,-71.650 --to 40.729,-73.966 --k 2 \
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--stop 42.2767,-71.806:60:cascade --stop 43.507,-71.548:50:ladd \
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--stop 43.902,-71.64:60:plymouth --stop 42.425,-71.68:60:brewsters
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# order: ladd -> cascade detour: 23 min
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```
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## Tests
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```sh
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go test ./... # unit tests, offline, fast
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go test -tags integration ./... # live router (Valhalla by default)
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ROUTER_BACKEND=osrm ROUTER_URL=http://localhost:5000 \
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go test -tags integration ./... # against local OSRM
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```
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The integration tests encode the key regression: the fastest
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Lincoln→Queens drive stays ≥15 km from Boston (it goes via Worcester,
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I-90/I-495/I-290). That is exactly the fact an LLM confidently gets wrong.
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## Benchmark
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```sh
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go run ./cmd/bench # valhalla goldens (bench/tasks.json)
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go run ./cmd/bench --tasks bench/tasks.osrm.json # local-OSRM goldens
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go run ./cmd/bench --record # re-record into the file you're running
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```
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Tasks are real OD pairs across NH/MA/CT/NY with real POI candidates and
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dwell times. **Goldens are per backend+profile** (see profile deltas
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below): `bench/tasks.json` carries Valhalla goldens, `bench/tasks.osrm.json`
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local-OSRM goldens. Both currently **26 PASS / 0 FAIL**, and both
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routers pick the *same* optimized orders for all 5 tasks despite their
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different clocks. Check types:
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| type | meaning |
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| `golden_route_min` | direct route time within a recorded band (±10%) |
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| `route_avoids` | route stays ≥ N km from a point (geometry, or bbox when the backend has none) |
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| `stop_free` / `stop_detour_at_least` / `stop_detour_band` | computed detour of a candidate vs an expected band |
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| `optimize_order` | the exhaustive optimum matches the recorded order |
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| `crosscheck` | single multi-waypoint route ≈ matrix-summed prediction (≤ maxPct drift) |
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Current state: **26 PASS / 0 FAIL** on both hosted Valhalla and local
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OSRM (separate golden files).
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## Self-hosted OSRM (full geometry, exact corridors) — verified
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`scripts/setup-osrm.sh` is the full, tested path (no sudo, no conan):
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`deps.sh` builds bzip2, Lua 5.2, oneTBB, Boost 1.84 (b2 + hand-rolled
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CMake config files — boost release tarballs ship no CMake support) and
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osmium-tool; then it builds OSRM 26.4.1, merges the 4 state PBFs
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(osrm-extract takes one input), extracts (~8 GB peak RAM, ~4 min),
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partitions, customizes, and serves on `:5000`. Artifacts live in
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`/tmp/osm-build` by default (set `W=` for a durable location).
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```sh
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ROUTER_BACKEND=osrm ROUTER_URL=http://localhost:5000 go test -tags integration ./...
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go run ./cmd/routectl route --backend osrm --from 44.054,-71.650 --to 40.729,-73.966
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# 6h50m, 514.4 km, 9068 geometry points (exact corridor available)
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```
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With OSRM, `Route.Geometry` is populated, so the corridor is exact
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(distances to the actual routed polyline) instead of the chord fallback
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used with the hosted Valhalla. This is what makes
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`search_along_route`'s spatial pre-filter (PostGIS `ST_DWithin` on the
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corridor polygon in the v1 design) sound.
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### Profile deltas matter (measured, same OD pair)
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| backend | Lincoln NH → Queens NY |
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| Valhalla `auto` | 332 min, 531 km |
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| OSRM `car` | 410 min, 514 km |
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Both avoid Boston (22 km vs 38 km clearance) and both take the
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I-93/90/495/290 corridor — same route *shape*, different *clocks*.
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Consequences: (a) goldens in `bench/tasks.json` are per
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backend+profile — re-record (`--record`) after switching; (b) any
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user-facing arrival-time math must use one backend consistently per
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trip and say which.
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## Design notes
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- **The route is computed, never narrated.** No function in this module
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returns a time estimate from model knowledge; every number is router
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output (`computed` provenance per DESIGN.md R4).
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- **Matrix via pairwise route calls.** Valhalla's
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`sources_to_targets` caps at 150 km, so the common path is
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`BuildMatrix` (pairwise `/route`). OSRM's `Table` service is available
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for the local backend when a single-call matrix matters.
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- **optimize_stops semantics**: the user asked for *k* stops ("two
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hikes"), so the objective minimizes total = detour + dwell + overhead
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over ordered subsets of **exactly k**, with fallback (a) to the best
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feasible smaller set when a time budget is given, then (b) to the best
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exactly-k ignoring the budget, flagged `Feasible=false`.
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"At most k" without a budget degenerates (zero stops always wins).
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- **Stop coordinates are POI centroids.** The router snaps to the
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network; a 200 m centroid error moves a 531 km route's detour by
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seconds, not minutes.
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