rung: 2
name: "Backend-Aware Stability Rung"
description: "Same [[4,2,2]] task, but with repeated cheap-tier runs, backend variation, and stronger stability pressure."
objective: "Favor experiment settings that hold score under calibration-like backend changes and repeated noisy evaluation."

bootstrap_incumbent:
  seed_style: h_p
  encoder_style: cx_chain
  verification: both
  postselection: all_measured
  ancilla_strategy: dedicated_pair
  optimization_level: 3
  layout_method: sabre
  routing_method: sabre
  approximation_degree: 1.0
  target_backend: fake_kyoto
  noise_backend: fake_kyoto
  shots: 768
  repeats: 3
  notes: "Stability-focused bootstrap incumbent."

search_space:
  max_challengers_per_step: 8
  dimensions:
    target_backend: [fake_kyoto, fake_brisbane, fake_sherbrooke]
    noise_backend: [fake_kyoto, fake_brisbane, fake_sherbrooke]
    verification: [both, z_only]
    postselection: [all_measured, z_only]
    optimization_level: [1, 2, 3]
    layout_method: [sabre, dense]
    routing_method: [sabre, basic]

tier_policy:
  cheap_margin: 0.001
  confirmation_margin: 0.0
  cheap_shots: 768
  expensive_shots: 1536
  cheap_repeats: 3
  expensive_repeats: 1
  promote_top_k: 2
  enable_hardware: false
  confirm_incumbent_on_hardware: true
  hardware_budget: 1

score:
  name: weighted_acceptance_cost
  base_cost: 1.0
  cheap_quality:
    noisy_fidelity: 0.30
    logical_witness: 0.25
    codespace_rate: 0.20
    stability_score: 0.20
    spectator_alignment: 0.05
  expensive_quality:
    logical_witness: 0.45
    codespace_rate: 0.15
    stability_score: 0.30
    spectator_alignment: 0.10
  cost_weights:
    two_qubit_count: 0.06
    depth: 0.01
    shot_count: 0.00025
    runtime_estimate: 0.02
    queue_cost_proxy: 0.35

step_budget: 3
patience: 2

hardware:
  backend_name:
  channel:
  instance:
  token_env_var: QISKIT_IBM_TOKEN