experiment: E3_region_matched_grounding
seed: 20260704
n_replicates: 100
generations: 400

# Region-matched grounding (blueprint 2.5-E3). Fixed total budget m; the lineage this
# passage exercises region 0 (the target, carrying its own rare tail). Compare:
#   uniform  -> spread m evenly over all R regions (region 0 gets only m/R)
#   matched  -> allocate m to the exercised region(s) only (region 0 gets all of m)
# Prediction: under uniform, region 0's tail collapses even though global grounding is
# nonzero; under matched, it persists. Metric: per-region tail-item survival.
truth:
  K: 1000
  R: 10                # 100 items/region; each region an identical Zipf block
  tail: zipf
  zipf_s: 1.1
  tail_frac: 0.5
  tail_threshold: 1.0e-3
  init: truth

dynamics:
  n: 200
  teachers: {K_T: 1, rho: 0.0, q: 1.0}
  grounding:
    m: 100             # same total for both arms; uniform => 10/region, matched => 100 to region 0
    policy: uniform    # overwritten by the sweep
    exercised: [0]     # region 0 is exercised this passage (matched targets it)
  selection: {mode: none, novelty_alpha: 0.0}
  remint: {enabled: false, period: null, H_gate: null}

metrics:
  kl_floor: 1.0e-9
  support_eps: 1.0e-9

sweep:
  - param: dynamics.grounding.policy
    values: [uniform, matched]

output:
  dir: results/figS5_aimed_grounding