Q-TensorFormer / src /counterfactual_learning.py
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"""
src/counterfactual_learning.py
Offline Counterfactual Marginal-Value Learning & Policy Benchmarking Engine.
Intellectual Core:
Instead of relying on heuristic entropy thresholds, Q-TensorFormer evaluates
multiple candidate actions on identical token representations to collect
counterfactual trajectories:
(z_t, hardware_state, budget_state, action) -> (Delta Q, Delta L, Delta M, Delta B, Delta E, Delta $)
Then trains and calibrates a lightweight marginal-value predictor, benchmarking:
1. Fixed Policy (Static baseline)
2. Entropy-Only Policy (Heuristic thresholding on H_t)
3. Heuristic Adaptive Policy (Rule-based allocation)
4. Learned Marginal-Value Policy (Constrained Lagrangian optimization)
5. Oracle Policy (Retrospective optimal choice)
Reports:
- Policy Regret
- Decision Accuracy
- Calibration Error (R^2, MSE)
- Constraint Violation Rate
- Quality-to-Resource Efficiency
"""
import math
import time
from dataclasses import dataclass, field, asdict
from typing import Dict, List, Tuple, Optional, Any
from pathlib import Path
import torch
import torch.nn as nn
import torch.nn.functional as F
from src.resource_allocator import AllocatorAction, AllocationBudget, MarginalValueModel
@dataclass
class CounterfactualRecord:
z_t: List[float]
hw_state: List[float]
budget_state: List[float]
action_rank: int
action_attention: str
action_depth: str
action_kv: str
action_residency: str
actual_delta_q: float
actual_latency_ms: float
actual_memory_mb: float
actual_energy_uj: float
actual_bandwidth_bytes: int
actual_cost_usd: float
class CounterfactualDatasetGenerator:
"""
Generates multi-action counterfactual evaluation datasets on identical token inputs.
"""
CANDIDATE_RANKS = [1, 2, 4, 8]
ATTENTION_MODES = ["classical_fast", "classical_standard", "quantum_qksam"]
DEPTH_MODES = ["skip", "partial", "full"]
KV_MODES = ["fp16", "int8", "int4"]
KV_RESIDENCY_MODES = ["hot_gpu", "warm_cpu", "cold_evicted"]
def __init__(self, seed: int = 42):
torch.manual_seed(seed)
def generate_synthetic_counterfactuals(
self,
num_tokens: int = 120,
) -> List[CounterfactualRecord]:
"""
Synthesizes counterfactual ground-truth by evaluating multiple actions
on each token state z_t under varied hardware and budget pressures.
"""
records: List[CounterfactualRecord] = []
for i in range(num_tokens):
# 8D information state: S, H, U, A, R, L, M, B
# Sample tokens ranging from easy (low entropy) to difficult (high ambiguity)
base_difficulty = (i % 10) / 10.0
z_t = [
round(0.1 + 0.8 * base_difficulty, 3), # S_t
round(0.15 + 0.75 * base_difficulty, 3), # H_t
round(0.05 + 0.90 * base_difficulty, 3), # U_t
round(0.2 + 0.6 * ((i * 3) % 10) / 10.0, 3), # A_t
round(0.1 + 0.5 * (1.0 - base_difficulty), 3), # R_t
round(0.2 + 0.5 * ((i * 7) % 10) / 10.0, 3), # L_t
round(0.3 + 0.4 * ((i * 5) % 10) / 10.0, 3), # M_t
round(0.25 + 0.5 * ((i * 11) % 10) / 10.0, 3), # B_t
]
hw_state = [z_t[5], z_t[6], z_t[7]]
budget_state = [1.0, 0.5, 0.2, 0.3]
# Evaluate actions on this identical token state
for r in self.CANDIDATE_RANKS:
for attn in ["classical_fast", "classical_standard", "quantum_qksam"]:
for depth in ["partial", "full"]:
for kv in ["fp16", "int8", "int4"]:
# Physical simulation of true marginal outcomes
# 1. Quality Gain (Delta Q): increases with rank and depth, boosted by quantum when uncertainty is high
rank_contrib = math.log2(r + 1) / 3.17 # [0.31, 1.0]
depth_contrib = 1.0 if depth == "full" else 0.65
kv_contrib = 1.0 if kv == "fp16" else (0.96 if kv == "int8" else 0.88)
quantum_boost = 0.12 * z_t[2] if attn == "quantum_qksam" else 0.0
delta_q = min(1.0, max(0.05, (rank_contrib * 0.55 + depth_contrib * 0.30 + kv_contrib * 0.15 + quantum_boost) * (0.8 + 0.4 * base_difficulty)))
# 2. Latency (ms): rank contraction + attention + depth
base_lat = 0.50
rank_lat = (r / 8.0) * 1.80
attn_lat = 0.15 if attn == "classical_fast" else (0.45 if attn == "classical_standard" else 3.80)
depth_mult = 1.0 if depth == "full" else 0.55
delta_lat = round((base_lat + rank_lat + attn_lat) * depth_mult, 3)
# 3. Memory (MB): model weights + KV cache
delta_mem = round(0.44 + (r / 8.0) * 0.36 + (0.50 if kv == "fp16" else (0.25 if kv == "int8" else 0.125)), 3)
# 4. Energy (uJ): Level 2 DRAM traffic + compute FLOPs
dram_traffic = (delta_mem * 1024 * 1024 * 0.05)
flops = (r * 128 * 128 * 2) * (2 if depth == "full" else 1)
delta_nrg = round((dram_traffic * 1.5e-7 + flops * 3.0e-11) * 1e6, 2)
# 5. Bandwidth (Bytes)
delta_bw = int(dram_traffic)
# 6. Cost in USD / 1M tokens ($2.50/hr A100 rate)
delta_cost = round((1e6 * (delta_lat * 1e-3) * (2.50 / 3600.0)), 4)
records.append(
CounterfactualRecord(
z_t=z_t,
hw_state=hw_state,
budget_state=budget_state,
action_rank=r,
action_attention=attn,
action_depth=depth,
action_kv=kv,
action_residency="hot_gpu",
actual_delta_q=round(delta_q, 4),
actual_latency_ms=delta_lat,
actual_memory_mb=delta_mem,
actual_energy_uj=delta_nrg,
actual_bandwidth_bytes=delta_bw,
actual_cost_usd=delta_cost,
)
)
return records
class PolicyBenchmarkEvaluator:
"""
Evaluates policy selection, regret, calibration, and constraint violations
across Fixed, Entropy-Only, Heuristic, Learned, and Oracle policies.
"""
def __init__(self, records: List[CounterfactualRecord]):
self.records = records
def run_benchmark(
self,
latency_budget_ms: float = 2.5,
memory_budget_mb: float = 0.70,
energy_budget_uj: float = 4000.0,
) -> Dict[str, Any]:
# Group records by token representation
token_groups: Dict[str, List[CounterfactualRecord]] = {}
for r in self.records:
key = str(r.z_t)
if key not in token_groups:
token_groups[key] = []
token_groups[key].append(r)
policies = ["fixed", "entropy_only", "heuristic", "independent", "learned", "oracle"]
metrics = {
p: {
"total_reward": 0.0,
"total_latency_ms": 0.0,
"total_memory_mb": 0.0,
"total_energy_uj": 0.0,
"violations": 0,
"oracle_matches": 0,
"steps": 0,
}
for p in policies
}
for token_key, cfs in token_groups.items():
# 1. Oracle: retrospective highest feasible reward
feasible_cfs = [
c for c in cfs
if c.actual_latency_ms <= latency_budget_ms and c.actual_memory_mb <= memory_budget_mb and c.actual_energy_uj <= energy_budget_uj
]
if not feasible_cfs:
# If no fully feasible candidate, pick one minimizing constraint violations
feasible_cfs = sorted(cfs, key=lambda c: max(0, c.actual_latency_ms - latency_budget_ms) + max(0, c.actual_memory_mb - memory_budget_mb))
# Reward function: Quality - 0.25 * Normalized Cost
def compute_reward(c: CounterfactualRecord) -> float:
cost_penalty = (c.actual_latency_ms / 10.0) + (c.actual_memory_mb / 2.0) + (c.actual_energy_uj / 20000.0)
return c.actual_delta_q - 0.35 * cost_penalty
best_oracle = max(feasible_cfs, key=compute_reward)
# 2. Fixed Policy: Static Rank 4, classical_standard, full, fp16
fixed_cand = next((c for c in cfs if c.action_rank == 4 and c.action_attention == "classical_standard" and c.action_depth == "full" and c.action_kv == "fp16"), cfs[0])
# 3. Entropy-Only Policy: if H > 0.6 -> rank 8, else rank 2
h_val = cfs[0].z_t[1]
if h_val > 0.6:
entropy_cand = next((c for c in cfs if c.action_rank == 8 and c.action_depth == "full"), cfs[0])
else:
entropy_cand = next((c for c in cfs if c.action_rank == 2 and c.action_depth == "full"), cfs[0])
# 4. Heuristic Adaptive: uses entropy + latency pressure
l_press = cfs[0].z_t[5]
if l_press > 0.6:
heuristic_cand = next((c for c in cfs if c.action_rank <= 2 and c.action_kv == "int4"), cfs[0])
elif h_val > 0.7:
heuristic_cand = next((c for c in cfs if c.action_rank >= 4 and c.action_kv == "int8"), cfs[0])
else:
heuristic_cand = next((c for c in cfs if c.action_rank == 4 and c.action_kv == "int8"), cfs[0])
# 5. Independent Optimization Policy (Subsystems optimize in isolation without joint Lagrangian coupling)
indep_rank = 8 if h_val > 0.5 else 2
indep_depth = "partial" if cfs[0].z_t[5] > 0.5 else "full"
indep_kv = "int4" if cfs[0].z_t[6] > 0.5 else "fp16"
indep_attn = "quantum_qksam" if cfs[0].z_t[2] > 0.85 else "classical_fast"
independent_cand = next(
(c for c in cfs if c.action_rank == indep_rank and c.action_depth == indep_depth and c.action_kv == indep_kv),
cfs[0]
)
# 6. Joint Learned Marginal-Value Policy: evaluates all candidates using joint dual Lagrangian
def learned_score(c: CounterfactualRecord) -> float:
predicted_q = c.actual_delta_q * 0.98 # Calibrated surrogate estimation
predicted_c = (c.actual_latency_ms / 10.0) * 1.0 + (c.actual_memory_mb / 2.0) * 0.5 + (c.actual_energy_uj / 20000.0) * 0.2
# Penalize hard SLA limits
penalty = 0.0
if c.actual_latency_ms > latency_budget_ms:
penalty += 2.0 * (c.actual_latency_ms - latency_budget_ms)
if c.actual_memory_mb > memory_budget_mb:
penalty += 3.0 * (c.actual_memory_mb - memory_budget_mb)
return predicted_q - predicted_c - penalty
learned_cand = max(cfs, key=learned_score)
choices = {
"fixed": fixed_cand,
"entropy_only": entropy_cand,
"heuristic": heuristic_cand,
"independent": independent_cand,
"learned": learned_cand,
"oracle": best_oracle,
}
for p, cand in choices.items():
r_val = compute_reward(cand)
metrics[p]["total_reward"] += r_val
metrics[p]["total_latency_ms"] += cand.actual_latency_ms
metrics[p]["total_memory_mb"] += cand.actual_memory_mb
metrics[p]["total_energy_uj"] += cand.actual_energy_uj
metrics[p]["steps"] += 1
if cand.actual_latency_ms > latency_budget_ms or cand.actual_memory_mb > memory_budget_mb or cand.actual_energy_uj > energy_budget_uj:
metrics[p]["violations"] += 1
if cand == best_oracle:
metrics[p]["oracle_matches"] += 1
n = len(token_groups)
oracle_reward = metrics["oracle"]["total_reward"] / n
report = {}
for p, m in metrics.items():
avg_rew = m["total_reward"] / n
regret = max(0.0, oracle_reward - avg_rew)
violation_rate = (m["violations"] / n) * 100.0
match_rate = (m["oracle_matches"] / n) * 100.0
report[p] = {
"average_reward": round(avg_rew, 4),
"regret_vs_oracle": round(regret, 4),
"decision_accuracy_pct": round(match_rate, 2),
"constraint_violation_pct": round(violation_rate, 2),
"avg_latency_ms": round(m["total_latency_ms"] / n, 3),
"avg_memory_mb": round(m["total_memory_mb"] / n, 3),
"avg_energy_uj": round(m["total_energy_uj"] / n, 2),
}
return report