NuCon/nucon/rl.py
Dominik Roth 65190dffea feat: uncertainty-aware training with penalty and abort
sim.py:
- simulator.update(return_uncertainty=True) calls forward_with_uncertainty
  on kNN models and returns the GP std; returns None for NN or when not
  requested (no extra cost if unused)
- No state stored on simulator; caller decides what to do with the value

rl.py (NuconEnv and NuconGoalEnv):
- uncertainty_penalty_start: above this GP std, subtract a linear penalty
  from the reward (scaled by uncertainty_penalty_scale, default 1.0)
- uncertainty_abort: at or above this GP std, set truncated=True
- Only calls update(return_uncertainty=True) when either threshold is set
- Uncertainty only applies when using a simulator (kNN model); ignored otherwise

Example:
    simulator = NuconSimulator()
    simulator.load_model('reactor_knn.pkl')
    env = NuconGoalEnv(..., simulator=simulator,
                       uncertainty_penalty_start=0.3,
                       uncertainty_abort=0.7,
                       uncertainty_penalty_scale=2.0)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-03-12 18:37:09 +01:00

424 lines
17 KiB
Python

import gymnasium as gym
from gymnasium import spaces
import numpy as np
import time
from typing import Dict, Any
from enum import Enum
from nucon import Nucon, BreakerStatus, PumpStatus, PumpDryStatus, PumpOverloadStatus
Objectives = {
"null": lambda obs: 0,
"max_power": lambda obs: obs["GENERATOR_0_KW"] + obs["GENERATOR_1_KW"] + obs["GENERATOR_2_KW"],
"episode_time": lambda obs: obs["EPISODE_TIME"],
}
Parameterized_Objectives = {
"target_temperature": lambda goal_temp: lambda obs: -((obs["CORE_TEMP"] - goal_temp) ** 2),
"target_gap": lambda goal_gap: lambda obs: -((obs["CORE_TEMP"] - obs["CORE_TEMP_MIN"] - goal_gap) ** 2),
"temp_below": lambda max_temp: lambda obs: -(np.clip(obs["CORE_TEMP"] - max_temp, 0, np.inf) ** 2),
"temp_above": lambda min_temp: lambda obs: -(np.clip(min_temp - obs["CORE_TEMP"], 0, np.inf) ** 2),
"constant": lambda constant: lambda obs: constant,
}
class NuconEnv(gym.Env):
metadata = {'render_modes': ['human']}
def __init__(self, nucon=None, simulator=None, render_mode=None, seconds_per_step=5, objectives=['null'], terminators=['null'], objective_weights=None, terminate_above=0,
uncertainty_penalty_start: float = None, uncertainty_abort: float = None, uncertainty_penalty_scale: float = 1.0):
super().__init__()
self.render_mode = render_mode
self.seconds_per_step = seconds_per_step
if objective_weights is None:
objective_weights = [1.0 for objective in objectives]
self.objective_weights = objective_weights
self.terminate_above = terminate_above
self.simulator = simulator
self.uncertainty_penalty_start = uncertainty_penalty_start
self.uncertainty_abort = uncertainty_abort
self.uncertainty_penalty_scale = uncertainty_penalty_scale
if nucon is None:
if simulator:
nucon = Nucon(port=simulator.port)
else:
nucon = Nucon()
self.nucon = nucon
# Define observation space
obs_spaces = {'EPISODE_TIME': spaces.Box(low=0, high=np.inf, shape=(1,), dtype=np.float32)}
for param_id, param in self.nucon.get_all_readable().items():
sp = _build_param_space(param)
if sp is not None:
obs_spaces[param_id] = sp
self.observation_space = spaces.Dict(obs_spaces)
# Define action space (only controllable, non-cheat, readable-back params)
action_spaces = {}
for param_id, param in self.nucon.get_all_writable().items():
if not param.is_readable or param.is_cheat:
continue # write-only (VALVE_OPEN/CLOSE, SCRAM, etc.) and cheat params excluded
sp = _build_param_space(param)
if sp is not None:
action_spaces[param_id] = sp
self.action_space = spaces.Dict(action_spaces)
self.objectives = []
self.terminators = []
for objective in objectives:
if objective in Objectives:
self.objectives.append(Objectives[objective])
elif callable(objective):
self.objectives.append(objective)
else:
raise ValueError(f"Unsupported objective: {objective}")
for terminator in terminators:
if terminator in Objectives:
self.terminators.append(Objectives[terminator])
elif callable(terminator):
self.terminators.append(terminator)
else:
raise ValueError(f"Unsupported terminator: {terminator}")
def _get_obs(self):
obs = {}
for param_id, param in self.nucon.get_all_readable().items():
if param.param_type == str or param_id not in self.observation_space.spaces:
continue
value = self.nucon.get(param_id)
if isinstance(value, Enum):
value = value.value
obs[param_id] = value
obs["EPISODE_TIME"] = self._total_steps * self.seconds_per_step
return obs
def _get_info(self):
info = {'objectives': {}, 'objectives_weighted': {}}
for objective, weight in zip(self.objectives, self.objective_weights):
obj = objective(self._get_obs())
info['objectives'][objective.__name__] = obj
info['objectives_weighted'][objective.__name__] = obj * weight
return info
def reset(self, seed=None, options=None):
super().reset(seed=seed)
self._total_steps = 0
observation = self._get_obs()
info = self._get_info()
return observation, info
def step(self, action):
# Apply the action to the Nucon system
for param_id, value in action.items():
param = self.nucon._parameters[param_id]
if issubclass(param.param_type, Enum):
value = param.param_type(int(np.asarray(value).flat[0]))
else:
value = param.param_type(np.asarray(value).flat[0])
if param.min_val is not None and param.max_val is not None:
value = np.clip(value, param.min_val, param.max_val)
self.nucon.set(param, value)
observation = self._get_obs()
terminated = np.sum([terminator(observation) for terminator in self.terminators]) > self.terminate_above
truncated = False
info = self._get_info()
reward = sum(obj for obj in info['objectives_weighted'].values())
self._total_steps += 1
if self.simulator:
needs_uncertainty = self.uncertainty_penalty_start is not None or self.uncertainty_abort is not None
uncertainty = self.simulator.update(self.seconds_per_step, return_uncertainty=needs_uncertainty)
if uncertainty is not None:
if self.uncertainty_abort is not None and uncertainty >= self.uncertainty_abort:
truncated = True
if self.uncertainty_penalty_start is not None and uncertainty > self.uncertainty_penalty_start:
reward -= self.uncertainty_penalty_scale * (uncertainty - self.uncertainty_penalty_start)
else:
sim_speed = self.nucon.GAME_SIM_SPEED.value or 1.0
time.sleep(self.seconds_per_step / sim_speed)
return observation, reward, terminated, truncated, info
def render(self):
if self.render_mode == "human":
pass
def close(self):
pass
def _flatten_action(self, action):
return np.concatenate([v.flatten() for v in action.values()])
def _unflatten_action(self, flat_action):
return {k: v.reshape(1, -1) for k, v in self.action_space.items()}
def _flatten_observation(self, observation):
return np.concatenate([v.flatten() for v in observation.values()])
def _unflatten_observation(self, flat_observation):
return {k: v.reshape(1, -1) for k, v in self.observation_space.items()}
def _build_param_space(param):
"""Return a gymnasium Box for a single NuconParameter, or None if unsupported."""
if param.param_type == float:
return spaces.Box(low=param.min_val or -np.inf, high=param.max_val or np.inf, shape=(1,), dtype=np.float32)
elif param.param_type == int:
lo = param.min_val if param.min_val is not None else -np.inf
hi = param.max_val if param.max_val is not None else np.inf
return spaces.Box(low=lo, high=hi, shape=(1,), dtype=np.float32)
elif param.param_type == bool:
return spaces.Box(low=0, high=1, shape=(1,), dtype=np.float32)
elif param.param_type == str:
return None
elif issubclass(param.param_type, Enum):
return spaces.Box(low=0, high=len(param.param_type) - 1, shape=(1,), dtype=np.float32)
return None
class NuconGoalEnv(gym.Env):
"""
Goal-conditioned reactor environment compatible with SB3 HER (Hindsight Experience Replay).
The observation is a Dict with three keys as required by GoalEnv / HER:
- 'observation': all readable non-goal, non-str params (same encoding as NuconEnv)
- 'achieved_goal': current values of goal_params, normalised to [0, 1] within goal_range
- 'desired_goal': target values sampled each episode, normalised to [0, 1]
Reward defaults to negative L2 distance in the normalised goal space (dense).
Pass ``tolerance`` for a sparse {0, -1} reward (0 = within tolerance).
Usage with SB3 HER::
from stable_baselines3 import SAC
from stable_baselines3.common.buffers import HerReplayBuffer
env = NuconGoalEnv(
goal_params=['GENERATOR_0_KW', 'GENERATOR_1_KW', 'GENERATOR_2_KW'],
goal_range={'GENERATOR_0_KW': (0, 1200), 'GENERATOR_1_KW': (0, 1200), 'GENERATOR_2_KW': (0, 1200)},
simulator=simulator,
)
model = SAC('MultiInputPolicy', env, replay_buffer_class=HerReplayBuffer)
model.learn(total_timesteps=200_000)
"""
metadata = {'render_modes': ['human']}
def __init__(
self,
goal_params,
goal_range=None,
reward_fn=None,
tolerance=None,
nucon=None,
simulator=None,
render_mode=None,
seconds_per_step=5,
terminators=None,
terminate_above=0,
uncertainty_penalty_start: float = None,
uncertainty_abort: float = None,
uncertainty_penalty_scale: float = 1.0,
):
super().__init__()
self.render_mode = render_mode
self.seconds_per_step = seconds_per_step
self.terminate_above = terminate_above
self.simulator = simulator
self.goal_params = list(goal_params)
self.tolerance = tolerance
if nucon is None:
nucon = Nucon(port=simulator.port) if simulator else Nucon()
self.nucon = nucon
all_readable = self.nucon.get_all_readable()
# Validate goal params and build per-param range arrays
for pid in self.goal_params:
if pid not in all_readable:
raise ValueError(f"Goal param '{pid}' is not a readable parameter")
goal_range = goal_range or {}
self._goal_low = np.array([
goal_range.get(pid, (all_readable[pid].min_val or 0.0, all_readable[pid].max_val or 1.0))[0]
for pid in self.goal_params
], dtype=np.float32)
self._goal_high = np.array([
goal_range.get(pid, (all_readable[pid].min_val or 0.0, all_readable[pid].max_val or 1.0))[1]
for pid in self.goal_params
], dtype=np.float32)
self._goal_range = self._goal_high - self._goal_low
self._goal_range[self._goal_range == 0] = 1.0 # avoid div-by-zero
self._reward_fn = reward_fn # callable(achieved_norm, desired_norm) -> float, or None
# Observation subspace: all readable non-str non-goal params
goal_set = set(self.goal_params)
obs_spaces = {'EPISODE_TIME': spaces.Box(low=0, high=np.inf, shape=(1,), dtype=np.float32)}
for param_id, param in all_readable.items():
if param_id in goal_set:
continue
sp = _build_param_space(param)
if sp is not None:
obs_spaces[param_id] = sp
n_goals = len(self.goal_params)
self.observation_space = spaces.Dict({
'observation': spaces.Dict(obs_spaces),
'achieved_goal': spaces.Box(low=0.0, high=1.0, shape=(n_goals,), dtype=np.float32),
'desired_goal': spaces.Box(low=0.0, high=1.0, shape=(n_goals,), dtype=np.float32),
})
# Action space: readable-back, non-cheat writable params
action_spaces = {}
for param_id, param in self.nucon.get_all_writable().items():
if not param.is_readable or param.is_cheat:
continue
sp = _build_param_space(param)
if sp is not None:
action_spaces[param_id] = sp
self.action_space = spaces.Dict(action_spaces)
# Terminators
self._terminators = terminators or []
self.uncertainty_penalty_start = uncertainty_penalty_start
self.uncertainty_abort = uncertainty_abort
self.uncertainty_penalty_scale = uncertainty_penalty_scale
self._desired_goal = np.zeros(n_goals, dtype=np.float32)
self._total_steps = 0
# ------------------------------------------------------------------
# GoalEnv interface
# ------------------------------------------------------------------
def compute_reward(self, achieved_goal, desired_goal, info):
"""
Dense: negative L2 in normalised goal space (each dim in [0,1]).
Sparse when tolerance is set: 0 if within tolerance, -1 otherwise.
Custom reward_fn overrides both.
"""
if self._reward_fn is not None:
return self._reward_fn(achieved_goal, desired_goal)
dist = np.linalg.norm(achieved_goal - desired_goal, axis=-1)
if self.tolerance is not None:
return (dist <= self.tolerance).astype(np.float32) - 1.0
return -dist
def _read_goal_values(self):
raw = np.array([
self.nucon.get(pid) or 0.0 for pid in self.goal_params
], dtype=np.float32)
return np.clip((raw - self._goal_low) / self._goal_range, 0.0, 1.0)
def _get_obs_dict(self):
obs = {'EPISODE_TIME': float(self._total_steps * self.seconds_per_step)}
goal_set = set(self.goal_params)
for param_id, param in self.nucon.get_all_readable().items():
if param_id in goal_set or param_id not in self.observation_space['observation'].spaces:
continue
value = self.nucon.get(param_id)
if isinstance(value, Enum):
value = value.value
obs[param_id] = value
achieved = self._read_goal_values()
return {
'observation': obs,
'achieved_goal': achieved,
'desired_goal': self._desired_goal.copy(),
}
def reset(self, seed=None, options=None):
super().reset(seed=seed)
self._total_steps = 0
# Sample a new goal uniformly from the goal range
rng = np.random.default_rng(seed)
self._desired_goal = rng.uniform(0.0, 1.0, size=len(self.goal_params)).astype(np.float32)
obs = self._get_obs_dict()
return obs, {}
def step(self, action):
for param_id, value in action.items():
param = self.nucon._parameters[param_id]
if issubclass(param.param_type, Enum):
value = param.param_type(int(np.asarray(value).flat[0]))
else:
value = param.param_type(np.asarray(value).flat[0])
if param.min_val is not None and param.max_val is not None:
value = np.clip(value, param.min_val, param.max_val)
self.nucon.set(param, value)
obs = self._get_obs_dict()
reward = float(self.compute_reward(obs['achieved_goal'], obs['desired_goal'], {}))
terminated = any(t(obs['observation']) > self.terminate_above for t in self._terminators)
truncated = False
info = {'achieved_goal': obs['achieved_goal'], 'desired_goal': obs['desired_goal']}
self._total_steps += 1
if self.simulator:
needs_uncertainty = self.uncertainty_penalty_start is not None or self.uncertainty_abort is not None
uncertainty = self.simulator.update(self.seconds_per_step, return_uncertainty=needs_uncertainty)
if uncertainty is not None:
if self.uncertainty_abort is not None and uncertainty >= self.uncertainty_abort:
truncated = True
if self.uncertainty_penalty_start is not None and uncertainty > self.uncertainty_penalty_start:
reward -= self.uncertainty_penalty_scale * (uncertainty - self.uncertainty_penalty_start)
else:
sim_speed = self.nucon.GAME_SIM_SPEED.value or 1.0
time.sleep(self.seconds_per_step / sim_speed)
return obs, reward, terminated, truncated, info
def render(self):
pass
def close(self):
pass
def register_nucon_envs():
gym.register(
id='Nucon-max_power-v0',
entry_point='nucon.rl:NuconEnv',
kwargs={'seconds_per_step': 5, 'objectives': ['max_power']}
)
gym.register(
id='Nucon-target_temperature_350-v0',
entry_point='nucon.rl:NuconEnv',
kwargs={'seconds_per_step': 5, 'objectives': [Parameterized_Objectives['target_temperature'](goal_temp=350)]}
)
gym.register(
id='Nucon-safe_max_power-v0',
entry_point='nucon.rl:NuconEnv',
kwargs={'seconds_per_step': 5, 'objectives': [Parameterized_Objectives['temp_above'](min_temp=310), Parameterized_Objectives['temp_below'](max_temp=365), 'max_power'], 'objective_weights': [1, 10, 1/100_000]}
)
# Goal-conditioned: target total generator output (train with HER)
gym.register(
id='Nucon-goal_power-v0',
entry_point='nucon.rl:NuconGoalEnv',
kwargs={
'goal_params': ['GENERATOR_0_KW', 'GENERATOR_1_KW', 'GENERATOR_2_KW'],
'goal_range': {'GENERATOR_0_KW': (0.0, 1200.0), 'GENERATOR_1_KW': (0.0, 1200.0), 'GENERATOR_2_KW': (0.0, 1200.0)},
'seconds_per_step': 5,
}
)
# Goal-conditioned: target core temperature (train with HER)
gym.register(
id='Nucon-goal_temp-v0',
entry_point='nucon.rl:NuconGoalEnv',
kwargs={
'goal_params': ['CORE_TEMP'],
'goal_range': {'CORE_TEMP': (280.0, 380.0)},
'seconds_per_step': 5,
}
)
register_nucon_envs()