Files
ashvale-station/tests/test_estimation.py
T
kemalandClaude Opus 5 2e6d84f17d Take Kalman tuning from config, not from the saved state
q and r were written into station_state.json and restored over the configured
values, so tuning was effectively immutable in the field. This was found the
expensive way: the retune in the previous commit was deployed, the service
restarted cleanly, and the filters carried on with q = 2e-6 because that is
what the state file said. Measured median rate afterwards was 14.4 C/h against
12.4 before, which is to say nothing happened.

Only the estimate is state. x, P and initialised are restored; q and r now
come from config every time. P may be momentarily inconsistent with a changed
q, which costs a few hundred samples of reconvergence and is far cheaper than
a configuration change that appears to work and does not.

load_dict also now skips filters this build no longer has, rather than
resurrecting them from an older state file.

Co-Authored-By: Claude Opus 5 <[email protected]>
2026-08-19 19:22:49 +01:00

367 lines
14 KiB
Python

# Copyright 2026 Kemal Yaylali
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Compensators and the Kalman bank.
The inverse-property tests here exist because getting that algebra wrong has
already cost this project twice: once on temperature, where a mismatched
simulator injected 1.2 C of phantom noise floor, and once on humidity, where
the correction ran the wrong way against a reference hygrometer.
"""
from __future__ import annotations
import numpy as np
import pytest
from ashvale.estimation import HumidityCompensator, KalmanCV, ThermalCompensator
from ashvale.physics import dew_point, saturation_vapour_pressure
# ---------------------------------------------------------------- thermal
def test_thermal_forward_model_is_the_exact_inverse_of_the_compensator():
"""T_raw = (T + k*T_cpu)/(1+k) must invert T = T_raw - k(T_cpu - T_raw)."""
for k, t_true, t_cpu in [(0.55, 19.0, 40.0), (0.26, 24.4, 40.2), (1.0, 5.0, 30.0)]:
c = ThermalCompensator(k0=k, k_min=0.0, k_max=2.0)
t_raw = (t_true + k * t_cpu) / (1.0 + k)
assert c.compensate(t_raw, t_cpu) == pytest.approx(t_true, abs=1e-9)
def test_thermal_calibration_moves_k_toward_the_truth():
c = ThermalCompensator(k0=0.30, k_min=0.05, k_max=1.5)
k_true, t_true, t_cpu = 0.62, 19.0, 41.0
t_raw = (t_true + k_true * t_cpu) / (1.0 + k_true)
before = abs(c.k - k_true)
c.calibrate(t_raw, t_cpu, t_true)
assert abs(c.k - k_true) < before
def test_thermal_clamp_survives_a_mistyped_reference():
c = ThermalCompensator(k0=0.55, k_min=0.15, k_max=1.20)
for _ in range(50):
c.calibrate(25.0, 40.0, -300.0) # absurd reference
assert c.k_min <= c.k <= c.k_max
def test_thermal_compensation_is_a_noop_without_a_gradient():
c = ThermalCompensator(k0=0.8)
assert c.compensate(21.0, 21.0) == pytest.approx(21.0)
# and never amplifies when the CPU is cooler than the sensor
assert c.compensate(21.0, 15.0) == pytest.approx(21.0)
# ---------------------------------------------------------------- humidity
def test_humidity_psychrometric_round_trip():
"""The simulator's forward model must invert the compensator exactly."""
rh_true, t_true, t_raw = 62.0, 19.0, 25.6
rh_sensor = rh_true * float(saturation_vapour_pressure(t_true) /
saturation_vapour_pressure(t_raw))
hc = HumidityCompensator(psychrometric=True)
assert hc.compensate(rh_sensor, t_raw, t_true) == pytest.approx(rh_true, abs=1e-6)
def test_humidity_psychrometric_preserves_dew_point():
"""Vapour pressure is the conserved quantity, so dew point must not move."""
rh_sensor, t_raw, t_true = 60.0, 25.6, 19.0
hc = HumidityCompensator(psychrometric=True)
out = hc.compensate(rh_sensor, t_raw, t_true)
assert float(dew_point(t_true, out)) == pytest.approx(float(dew_point(t_raw, rh_sensor)),
abs=1e-6)
def test_humidity_psychrometric_disabled_by_default():
hc = HumidityCompensator()
assert hc.compensate(60.0, 25.6, 19.0) == pytest.approx(60.0)
def test_humidity_offset_converges_on_a_reference():
"""The measured case: board reads 75.35% where the truth is 50.4%."""
hc = HumidityCompensator()
errors = []
for _ in range(6):
hc.calibrate(75.35, 27.94, 24.86, 50.4)
errors.append(abs(hc.compensate(75.35, 27.94, 24.86) - 50.4))
assert errors[-1] < errors[0]
assert errors[-1] < 0.5
def test_humidity_offset_is_clamped():
hc = HumidityCompensator()
for _ in range(50):
hc.calibrate(50.0, 20.0, 20.0, 100.0)
assert hc.off_min <= hc.offset <= hc.off_max
def test_humidity_output_stays_in_range():
hc = HumidityCompensator(offset=30.0)
assert 0.0 <= hc.compensate(95.0, 20.0, 20.0) <= 100.0
hc2 = HumidityCompensator(offset=-30.0)
assert 0.0 <= hc2.compensate(5.0, 20.0, 20.0) <= 100.0
def test_humidity_state_round_trips_through_dict():
hc = HumidityCompensator(offset=-24.2, psychrometric=True)
hc.calibrate(70.0, 25.0, 21.0, 50.0)
back = HumidityCompensator.from_dict(hc.to_dict())
assert back.offset == pytest.approx(hc.offset)
assert back.psychrometric is hc.psychrometric
assert back.n_calibrations == hc.n_calibrations
# ---------------------------------------------------------------- kalman
def test_kalman_covariance_stays_symmetric_and_psd():
"""Joseph form exists precisely so this holds over a long run."""
kf = KalmanCV(q=1e-6, r=0.05)
rng = np.random.default_rng(7)
for _ in range(20000):
kf.update(20.0 + 0.05 * rng.normal(), 2.0)
P = np.asarray(kf.P, dtype=float)
assert np.allclose(P, P.T, atol=1e-12)
assert np.all(np.linalg.eigvalsh(P) > -1e-12)
def test_kalman_tracks_a_constant_and_reports_zero_rate():
kf = KalmanCV(q=1e-8, r=0.01)
for _ in range(2000):
kf.update(15.0, 2.0)
assert kf.level == pytest.approx(15.0, abs=1e-3)
assert kf.rate == pytest.approx(0.0, abs=1e-5)
def test_kalman_recovers_a_known_ramp_rate():
kf = KalmanCV(q=1e-4, r=0.01)
true_rate = 0.5 / 3600.0 # 0.5 units per hour
for i in range(6000):
kf.update(10.0 + true_rate * i * 2.0, 2.0)
assert kf.rate * 3600.0 == pytest.approx(0.5, rel=0.05)
def test_kalman_ignores_non_finite_measurements():
kf = KalmanCV(q=1e-6, r=0.05)
kf.update(20.0, 2.0)
lvl_before = kf.level
kf.update(float("nan"), 2.0)
assert kf.level == pytest.approx(lvl_before)
def test_kalman_nis_is_near_one_when_noise_matches_the_model():
"""NIS is the honest self-check: consistent filter, NIS about 1."""
r = 0.04
kf = KalmanCV(q=1e-7, r=r)
rng = np.random.default_rng(11)
nis = []
for i in range(4000):
kf.update(18.0 + np.sqrt(r) * rng.normal(), 2.0)
if i > 500:
nis.append(kf.nis)
assert 0.5 < float(np.mean(nis)) < 2.0
def test_kalman_state_round_trips_through_dict():
kf = KalmanCV(q=1e-6, r=0.05)
for _ in range(50):
kf.update(12.0, 2.0)
back = KalmanCV.from_dict(kf.to_dict())
assert back.level == pytest.approx(kf.level)
assert back.rate == pytest.approx(kf.rate)
# ---------------------------------------------------------------- thermostat
def test_thermostat_reversion_is_first_order_and_preserves_dew_point():
"""A heated room is a closed loop, and heating adds no moisture.
Two properties, both easy to get wrong. The temperature must close the gap
to the setpoint exponentially rather than jumping or drifting, and the
implied humidity change must leave the dew point exactly where it was: RH
falls only because es(T) rose, which is why a heated house in winter is dry.
"""
import math
from ashvale.config import load_config
from ashvale.physics import dew_point, saturation_vapour_pressure
from ashvale.station import Station
cfg = load_config()
cfg.site.heating = True
cfg.site.heating_setpoint_c = 23.0
cfg.site.thermal_time_constant_h = 1.5
st = Station(cfg)
st.live = {"temp_smooth": 18.0}
tau = 1.5 * 3600.0
for h in (900, 3600, 10800, 86400):
expected = (23.0 - 18.0) * (1.0 - math.exp(-h / tau))
assert st._setpoint_delta("temperature", h, 18.0) == pytest.approx(expected, rel=1e-9)
# monotonic toward the setpoint, never past it
deltas = [st._setpoint_delta("temperature", h, 18.0)
for h in (900, 3600, 10800, 21600, 86400)]
assert all(a < b for a, b in zip(deltas, deltas[1:]))
assert deltas[-1] <= 5.0 + 1e-9
# dew point invariant
t0, rh0 = 18.0, 55.0
d_t = st._setpoint_delta("temperature", 86400, t0)
d_rh = st._setpoint_delta("humidity", 86400, rh0)
assert float(dew_point(t0 + d_t, rh0 + d_rh)) == pytest.approx(
float(dew_point(t0, rh0)), abs=1e-6)
assert d_rh < 0.0, "warming a room at constant moisture must lower RH"
assert float(saturation_vapour_pressure(t0 + d_t)) > float(
saturation_vapour_pressure(t0))
# a thermostat cannot move the synoptic field
assert st._setpoint_delta("pressure", 86400, 1013.0) == 0.0
# and off, the member is exactly persistence
cfg.site.heating = False
assert st._setpoint_delta("temperature", 86400, 18.0) == 0.0
assert st._setpoint_delta("humidity", 86400, 55.0) == 0.0
def test_forecast_head_migrates_state_from_before_the_setpoint_member():
"""An old save has three weights where there are now four."""
from ashvale.models.nowcast import MEMBERS, ForecastHead
h = ForecastHead(target="temperature", horizon_s=900, n_features=4)
state = h.to_dict()
state["weights"] = [0.2, 0.3, 0.5] # a pre-setpoint save
state["member_mae"] = [0.4, 0.5, 0.6]
back = ForecastHead.from_dict(state)
assert back.weights.size == len(MEMBERS)
assert float(back.weights.sum()) == pytest.approx(1.0)
# member_mae must migrate too. Missing it did not fail on load, it failed
# later inside learn() on a broadcast error, which is a worse place to
# discover a migration bug.
assert back.member_mae.size == len(MEMBERS)
back.learn(np.zeros(4), 20.0, 20.5, 0.1, 0.2) # must not raise
# ------------------------------------------------- dual-thermometer fusion
def _bare_board():
from ashvale.sensors import SD_HTS221, SD_LPS25HB, SenseBoard, _ChannelNoise
b = SenseBoard.__new__(SenseBoard)
b._noise_h = _ChannelNoise(SD_HTS221)
b._noise_p = _ChannelNoise(SD_LPS25HB)
b._gradient = None
b._gradient_lam = 0.9967
return b
def _two_channels(n=4000, seed=5):
from ashvale.sensors import K_HTS221, K_LPS25HB
rng = np.random.default_rng(seed)
cpu = 43.0 + 0.5 * np.sin(np.arange(n) / 500.0)
th = (24.0 + K_HTS221 * cpu) / (1 + K_HTS221) + 0.049 * rng.normal(size=n)
tp = (24.0 + K_LPS25HB * cpu) / (1 + K_LPS25HB) + 0.007 * rng.normal(size=n)
return th, tp
def test_fusion_does_not_move_the_mean():
"""The whole point of removing the gradient first.
The two chips stand about 1.3 C apart, so weighting them by variance drags
temp_raw onto the quieter one. k was fitted against the mean of the two, and
after the 1.55x gain of the inverse model that shift becomes about a degree
of silent bias on every reading downstream.
"""
th, tp = _two_channels()
board = _bare_board()
fused = np.array([board._fuse(th[i], tp[i])[0] for i in range(th.size)])
avg = (th + tp) / 2.0
w = slice(1000, None)
assert abs(fused[w].mean() - avg[w].mean()) < 0.01, "fusion shifted the calibration"
def test_fusion_is_quieter_than_the_average():
th, tp = _two_channels()
board = _bare_board()
fused = np.array([board._fuse(th[i], tp[i])[0] for i in range(th.size)])
avg = (th + tp) / 2.0
w = slice(1000, None)
def wn(x):
return np.std(np.diff(x)) / np.sqrt(2)
assert wn(fused[w]) < wn(avg[w]) / 2.0, "fusion did not halve the noise"
def test_fusion_survives_one_dead_channel():
board = _bare_board()
value, var = board._fuse(float("nan"), 29.5)
assert value == 29.5, "a dead HTS221 must not poison the reading"
value, var = board._fuse(30.5, float("nan"))
assert value == 30.5
value, var = board._fuse(float("nan"), float("nan"))
assert not np.isfinite(value)
def test_kalman_rate_is_physical_in_a_still_room():
"""The tuning failure this guards against.
On a real station the temperature filter reported a median rate of
12.4 C/h while the room moved 0.37 C/h. Process noise was set to track
perhaps a hundred times faster than any of these signals actually move.
"""
from ashvale.config import CONFIG
from ashvale.estimation import KalmanCV
dt = CONFIG.sensor.sample_period_s
rng = np.random.default_rng(3)
n = 6000
truth = 24.0 + 0.4 * np.arange(n) * dt / 3600.0 # a real 0.4 C/h drift
z = truth + 0.0877 * rng.normal(size=n) # measured input noise
kf = KalmanCV(CONFIG.sensor.kalman_q_temp, CONFIG.sensor.kalman_r_temp)
rates = [kf.update(z[i], dt)[1] * 3600.0 for i in range(n)]
settled = np.abs(np.array(rates[600:]))
assert np.median(settled) < 3.0, (
f"median |rate| {np.median(settled):.1f} C/h in a room drifting 0.4 C/h")
assert np.percentile(settled, 95) < 10.0
def test_retuning_q_survives_a_reload():
"""Tuning lives in config, not in the state file.
q and r were persisted and restored, so a retune deployed to a running
station did nothing: the service restarted and the filters carried on with
whatever tuning was in force when the state was last written. The symptom
is a config change that appears to work and does not, which is the worst
kind.
"""
from ashvale.config import load_config
from ashvale.estimation import SignalTracker
cfg = load_config()
cfg.sensor.kalman_q_temp = 2.0e-6 # an old, badly tuned state file
old = SignalTracker(cfg)
for i in range(50):
old.step(1.7554e9 + i * 2.0, 24.0, 50.0, 1013.0, 43.0)
saved = old.to_dict()
assert saved["filters"]["temperature"]["q"] == 2.0e-6
cfg.sensor.kalman_q_temp = 1.0e-9 # the retune
fresh = SignalTracker(cfg)
fresh.load_dict(saved)
assert fresh.filters["temperature"].q == 1.0e-9, \
"the state file overrode the configured tuning"
# the estimate itself must still be carried across
assert fresh.filters["temperature"].initialised
assert fresh.filters["temperature"].x[0] == pytest.approx(
old.filters["temperature"].x[0])