experiment: llm_epistasis_compat
kind: llm_epistasis
seed: 1
seeds: [1, 2, 3]
n_replicates: 1

# The missing CONTROL axis for the decisive experiment (identified from the first grid's results,
# 2026-08-11): in the original grid every shared-data pair was a CONFLICTED pair, so the delta-cosine
# geometry predictor could succeed as a mere task-OVERLAP detector (overlap coincided with conflict by
# construction). This sweep adds overlap WITHOUT conflict: both children train on the SAME ambiguous
# prompts with the SAME convention (asc/asc), private budgets fixed, at the same fractions as the
# conflict sweep. Pre-registered readings: if delta_cos stays high here while merge_penalty stays ~0,
# geometry was detecting overlap, not incompatibility, and its apparent predictive power collapses
# once compat pairs enter the pool; functional measures (epi_conf / dis_raw) should correctly stay LOW
# here (the parents AGREE on the shared prompts). If geometry still predicts across all three axes, the
# falsifier stands as stated in configs/llm/epistasis.yaml.

base_model: Qwen/Qwen2.5-0.5B-Instruct
family_a: strings
family_b: arith
n_train: 400
n_test: 80
epochs: 3
n_probe_each: 30
grad_k: 32
lora: {r: 16, alpha: 32}
compat_fracs: [0.25, 0.5, 0.75, 1.0]

output: {dir: results/llm_epistasis_compat}