Quickstart

A discovery campaign with an exact answer: locate the critical temperature of the 2D Ising model by maximizing the magnetic susceptibility under a fixed compute budget. Onsager’s exact result, \(T_c = 2/\ln(1+\sqrt{2}) \approx 2.269\), provides the ground truth against which any driver can be validated.

from cadaques import Budget, Campaign, Cost
from cadaques.drivers import AnnealedLocalDriver
from cadaques.oracles import Ising2DOracle, T_C_EXACT

oracle = Ising2DOracle(seed=0)
driver = AnnealedLocalDriver(
    space={"T": (1.5, 3.5)},
    fidelity={"L": 24, "sweeps": 400},
    seed=0,
)
campaign = Campaign(oracle, driver, Budget(total=Cost(seconds=30.0)))

outcome = campaign.run()
print(f"Best T = {outcome.best.query.params['T']:.3f}  (exact: {T_C_EXACT:.3f})")
print(f"Queries: {outcome.n_queries}, stop reason: {outcome.stop_reason}")
print(f"Spent: {outcome.budget.spent}")

The campaign ends when the budget is exhausted — not when an iteration counter runs out — and every transaction (declared and settled cost, timestamped) is recorded in the Ledger, exportable to JSONL as a complete, replayable trace.