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PHANTOM/sim/rl/jax_core/separability.py

68 lines
1.9 KiB
Python

"""Vectorized KL divergence for separability scoring."""
import numpy as np
from typing import Tuple
from lib.agent_probability import (
DEFAULT_AGENT_PRIOR,
estimate_agent_probability_batch,
)
try:
import jax.numpy as jnp
from jax import jit
JAX_AVAILABLE = True
except ImportError:
jnp, JAX_AVAILABLE = np, False
def jit(f):
return f
@jit
def batch_kl(P, Q_human, Q_agent, eps=1e-10):
"""Compute KL(P||Q) for batched P. P:(n,s,s), Q:(s,s). Returns (delta_h, delta_a) each (n,)."""
p = P + eps
p = p / p.sum(axis=-1, keepdims=True)
qh, qa = Q_human[None] + eps, Q_agent[None] + eps
delta_h = jnp.sum(p * jnp.log(p / qh), axis=(1, 2))
delta_a = jnp.sum(p * jnp.log(p / qa), axis=(1, 2))
return delta_h, delta_a
def compute_divergences(
session_trans: np.ndarray, ref_human: np.ndarray, ref_agent: np.ndarray
) -> Tuple[np.ndarray, np.ndarray]:
"""Compute KL divergence of each session from human/agent prototypes."""
if JAX_AVAILABLE:
dh, da = batch_kl(
jnp.array(session_trans), jnp.array(ref_human), jnp.array(ref_agent)
)
return np.asarray(dh), np.asarray(da)
# numpy fallback
eps = 1e-10
p = session_trans + eps
p = p / p.sum(axis=-1, keepdims=True)
qh, qa = ref_human[None] + eps, ref_agent[None] + eps
delta_h = np.sum(p * np.log(p / qh), axis=(1, 2))
delta_a = np.sum(p * np.log(p / qa), axis=(1, 2))
return delta_h, delta_a
def estimate_alpha_batch(
prob_agent: np.ndarray,
delta_h: np.ndarray,
delta_a: np.ndarray,
temp: float = 1.0,
prior_agent: float = DEFAULT_AGENT_PRIOR,
) -> np.ndarray:
"""Vectorized alpha estimation using divergence gap mapping."""
_ = prob_agent
return estimate_agent_probability_batch(
delta_h=np.asarray(delta_h, dtype=float),
delta_a=np.asarray(delta_a, dtype=float),
temperature=temp,
prior_agent=prior_agent,
)