|
2 | 2 |
|
3 | 3 | import equinox as eqx |
4 | 4 | import jax |
| 5 | +import pytest |
5 | 6 | from jax import numpy as jnp |
6 | 7 | from jax import random as jr |
7 | 8 |
|
8 | 9 | from oryx.algorithm import PPO |
9 | 10 | from oryx.policy.actor_critic import CustomActorCriticPolicy |
10 | 11 | from oryx.space import Box |
| 12 | +from tests.buffers import empty_buffer |
11 | 13 | from tests.envs import EchoEnv |
| 14 | +from tests.policies import ConstantPolicy |
12 | 15 |
|
13 | 16 |
|
14 | 17 | def _make_ppo(num_steps: int = 8) -> tuple[PPO, eqx.nn.State]: |
@@ -86,3 +89,95 @@ def test_learn_integration(self): |
86 | 89 | pol_state = state.substate(policy) |
87 | 90 | pol_state, act = policy.predict(pol_state, obs, key=jr.key(5)) |
88 | 91 | assert env.action_space.contains(act) |
| 92 | + |
| 93 | + def test_ppo_loss_clip_vs_unclipped_and_entropy(self): |
| 94 | + buf = empty_buffer(n=6) |
| 95 | + pol = ConstantPolicy(new_value=5.0, logp=0.0, entropy_val=2.0) |
| 96 | + |
| 97 | + loss_c, stats_c = PPO.ppo_loss( |
| 98 | + pol, |
| 99 | + buf, |
| 100 | + normalize_advantages=False, |
| 101 | + clip_coefficient=0.1, |
| 102 | + clip_value_loss=True, |
| 103 | + value_loss_coefficient=0.5, |
| 104 | + state_magnitude_coefficient=0.0, |
| 105 | + entropy_loss_coefficient=0.01, |
| 106 | + ) |
| 107 | + policy_loss = -1.0 |
| 108 | + value_loss_clipped = 0.5 * (0.1**2) |
| 109 | + entropy = 2.0 |
| 110 | + expected_total = policy_loss + 0.5 * value_loss_clipped - 0.01 * entropy |
| 111 | + |
| 112 | + assert float(stats_c.policy_loss) == pytest.approx(policy_loss) |
| 113 | + assert float(stats_c.value_loss) == pytest.approx(value_loss_clipped) |
| 114 | + assert float(stats_c.entropy_loss) == pytest.approx(entropy) |
| 115 | + assert float(stats_c.state_magnitude_loss) == pytest.approx(0.0) |
| 116 | + assert float(stats_c.total_loss) == pytest.approx(expected_total, rel=1e-6) |
| 117 | + assert float(stats_c.approx_kl) == pytest.approx(0.0) |
| 118 | + |
| 119 | + loss_u, stats_u = PPO.ppo_loss( |
| 120 | + pol, |
| 121 | + buf, |
| 122 | + normalize_advantages=False, |
| 123 | + clip_coefficient=0.1, |
| 124 | + clip_value_loss=False, |
| 125 | + value_loss_coefficient=0.5, |
| 126 | + state_magnitude_coefficient=0.0, |
| 127 | + entropy_loss_coefficient=0.01, |
| 128 | + ) |
| 129 | + assert float(stats_u.value_loss) == pytest.approx(12.5) |
| 130 | + expected_total_unclipped = policy_loss + 0.5 * 12.5 - 0.01 * entropy |
| 131 | + assert float(stats_u.total_loss) == pytest.approx( |
| 132 | + expected_total_unclipped, rel=1e-6 |
| 133 | + ) |
| 134 | + assert expected_total_unclipped != pytest.approx(expected_total) |
| 135 | + |
| 136 | + |
| 137 | +def _setup_algo(*, anneal: bool): |
| 138 | + key = jr.key(0) |
| 139 | + env = EchoEnv(space=Box(-jnp.ones(2), jnp.ones(2))) |
| 140 | + policy, _ = eqx.nn.make_with_state(CustomActorCriticPolicy)(env=env, key=key) |
| 141 | + algo, state = eqx.nn.make_with_state(PPO)( |
| 142 | + env=env, |
| 143 | + policy=policy, |
| 144 | + num_steps=8, |
| 145 | + num_epochs=2, |
| 146 | + num_mini_batches=2, |
| 147 | + learning_rate=1e-3, |
| 148 | + anneal_learning_rate=anneal, |
| 149 | + ) |
| 150 | + return algo, state |
| 151 | + |
| 152 | + |
| 153 | +def _collect_once(algo, state, *, key): |
| 154 | + state, carry = algo.initialize_iteration_carry(state, key=key) |
| 155 | + state, _, buf, _ = algo.collect_rollout( |
| 156 | + algo.policy, state, carry.step_carry, key=jr.split(key)[0] |
| 157 | + ) |
| 158 | + return state, buf |
| 159 | + |
| 160 | + |
| 161 | +def test_learning_rate_anneals_down(): |
| 162 | + algo, state = _setup_algo(anneal=True) |
| 163 | + state, buf = _collect_once(algo, state, key=jr.key(1)) |
| 164 | + |
| 165 | + lr0 = float(algo.learning_rate(state)) |
| 166 | + state, _, _ = algo.train(state, algo.policy, buf, key=jr.key(2)) |
| 167 | + lr1 = float(algo.learning_rate(state)) |
| 168 | + state, _, _ = algo.train(state, algo.policy, buf, key=jr.key(3)) |
| 169 | + lr2 = float(algo.learning_rate(state)) |
| 170 | + |
| 171 | + assert lr0 > lr1 > lr2 |
| 172 | + |
| 173 | + |
| 174 | +def test_learning_rate_constant_when_no_anneal(): |
| 175 | + algo, state = _setup_algo(anneal=False) |
| 176 | + state, buf = _collect_once(algo, state, key=jr.key(4)) |
| 177 | + |
| 178 | + lr0 = float(algo.learning_rate(state)) |
| 179 | + state, _, _ = algo.train(state, algo.policy, buf, key=jr.key(5)) |
| 180 | + lr1 = float(algo.learning_rate(state)) |
| 181 | + |
| 182 | + assert lr0 == pytest.approx(1e-3) |
| 183 | + assert lr1 == pytest.approx(lr0) |
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