Under a time limit, Irregular often finished in about a second and left
the rest unused: on the converted Nestbolt b-jakobs1 job it used five
sheets where four fit.
NestJobOptions.SearchUntilCancelled asks an engine to keep searching
after its normal search until the token is cancelled.
DeadlineNestingEngine sets it. Irregular then re-runs its six variants
with seeded per-type weights on its placement rule (seeds 1, 2, 3, ...,
each weight within e^+-0.4), reports each plan that beats its best,
then re-plans that plan's tail and reports any gain. It skips this when
the token cannot be cancelled, nobody listens for progress, nothing is
placeable, or the job has one part type, so unlimited solves are
unchanged.
Default now runs Irregular last (Rectangles, Circles, Irregular) so
Circles still runs, and chooses only after every candidate has run, in
tie-break order, so the run order never changes the choice. Unlimited
choices match the old run order {Rectangles, Irregular, Circles} except
when three candidates are near-tied within the 1e-9 comparison
tolerance without being transitively ordered (only on all-round jobs,
where Circles bids).
b-jakobs1 on one CPU, 10 s limit: 5 sheets (4.500) -> 4 (3.751).
DeadlineNestingEngine used CancelAfter, a thread-pool timer. A CPU-bound
Parallel.For keeps pool threads on their own local work, so the timer
callback can run seconds late; pinned to one CPU it waited for the
whole best-fit search (m-sign-3 under a 10 s limit returned at 64.5 s).
A dedicated background thread now waits for the limit, or for the
solve to finish, and cancels; the solve joins it before returning.
A test runs a CPU-bound Parallel.For from a pool thread under a 200 ms
limit and requires the solve to end within 3 s; with CancelAfter it
took about 7 s.
DeadlineNestingEngine wraps any engine with a wall-clock limit (any positive time up to
the cancellation timer's ~49.7 days). An engine that finishes in time
keeps its result, as does a result it returns after the limit. When the
limit cancels it, the best whole-job plan it reported (PlanImproved,
ranked like Default ranks candidates, a tie going to the later plan) is
returned if it passes the layout check; with none the solve fails with
TimeoutException. The caller's own cancellation is never turned into a
result. Engine plate commits are dropped and the returned result's
commits reported once it is known; plans are forwarded only when they
beat every plan shown so far.
Default now runs Rectangles, then Irregular, then Circles, so a search
stopped early already holds a valid plan. Ties still break by candidate
order (Irregular, Rectangles, Circles), so for these three the choice is
unchanged, and when every candidate throws, the first in that order is
still the one rethrown. A test seam takes a run order. Desktop, Console
and MCP do not apply a limit yet; Console can solve a job twice (cutout
trial and plain), which needs one shared deadline.
Mutations killed (10/10): no fallback at the limit, invalid plan
accepted, caller cancellation becomes a result, engine commits
forwarded, a worse later plan replaces the best, a tie keeps the earlier
plan, no upper limit bound, failure rethrown in run order, built-in run
order unchanged, run order ignored.
aj