prop/test/microwaveprop/propagation/model_test.exs
Graham McIntire a6b89961f6
feat(ml): retrain propagation model and add per-prediction explainability
Retrained on 60k month-balanced HRRR profiles through 2026-04-05
(test RMSE 1.7 score points, R² 0.97). Added explain_prediction/4
returning ranked feature contributions via batched finite-difference
attribution, so the UI can show users which weather factors drove
each prediction.
2026-04-28 14:14:22 -05:00

306 lines
9 KiB
Elixir

defmodule Microwaveprop.Propagation.ModelTest do
use ExUnit.Case, async: true
alias Microwaveprop.Propagation.Model
describe "build/0" do
test "returns an Axon model" do
model = Model.build()
assert %Axon{} = model
end
end
describe "init/0" do
test "returns initialized model state with parameters" do
params = Model.init()
assert %Axon.ModelState{} = params
assert Map.has_key?(params.data, "hidden_1")
assert Map.has_key?(params.data, "hidden_2")
assert Map.has_key?(params.data, "hidden_3")
assert Map.has_key?(params.data, "output")
end
end
describe "save/2 and load/1" do
@tag :tmp_dir
test "round-trips parameters to disk", %{tmp_dir: tmp_dir} do
path = Path.join(tmp_dir, "test_model.nx")
params = Model.init()
assert :ok = Model.save(params, path)
assert File.exists?(path)
assert {:ok, loaded} = Model.load(path)
# Predict with both and compare
input = Nx.broadcast(0.5, {1, 20})
original = Model.predict(params, input)
reloaded = Model.predict(loaded, input)
assert Nx.to_flat_list(original) == Nx.to_flat_list(reloaded)
end
test "load returns :error for missing file" do
assert :error = Model.load("/tmp/nonexistent_model.nx")
end
end
describe "load_or_init/1" do
@tag :tmp_dir
test "loads from file when it exists", %{tmp_dir: tmp_dir} do
path = Path.join(tmp_dir, "test_model.nx")
params = Model.init()
Model.save(params, path)
loaded = Model.load_or_init(path)
input = Nx.broadcast(0.5, {1, 20})
assert Nx.to_flat_list(Model.predict(params, input)) == Nx.to_flat_list(Model.predict(loaded, input))
end
test "initializes when file missing" do
params = Model.load_or_init("/tmp/nonexistent_model.nx")
assert %Axon.ModelState{} = params
end
end
describe "predict/2" do
test "produces output in [0, 1] range" do
params = Model.init()
# Single sample, 20 features
input = Nx.broadcast(0.5, {1, 20})
output = Model.predict(params, input)
assert Nx.shape(output) == {1, 1}
value = output |> Nx.to_flat_list() |> hd()
assert value >= 0.0 and value <= 1.0
end
test "handles batch of multiple samples" do
params = Model.init()
input = Nx.broadcast(0.5, {4, 20})
output = Model.predict(params, input)
assert Nx.shape(output) == {4, 1}
end
end
describe "encode_features/1" do
test "returns 20-element list" do
features =
Model.encode_features(%{
surface_temp_c: 25.0,
surface_dewpoint_c: 15.0,
surface_pressure_mb: 1015.0,
min_refractivity_gradient: -80.0,
hpbl_m: 600.0,
pwat_mm: 25.0,
utc_hour: 18,
month: 7,
freq_mhz: 10_000
})
assert length(features) == 20
assert Enum.all?(features, &is_float/1)
end
test "uses defaults for missing values" do
features = Model.encode_features(%{})
assert length(features) == 20
assert Enum.all?(features, &is_float/1)
end
test "cyclical encoding: hour 0 and hour 24 produce same sin/cos" do
f0 = Model.encode_features(%{utc_hour: 0})
f24 = Model.encode_features(%{utc_hour: 24})
# sin/cos at indices 8, 9
assert_in_delta Enum.at(f0, 8), Enum.at(f24, 8), 0.001
assert_in_delta Enum.at(f0, 9), Enum.at(f24, 9), 0.001
end
test "log_freq_mhz is last feature" do
features = Model.encode_features(%{freq_mhz: 10_000})
assert_in_delta List.last(features), :math.log(10_000) / 13.0, 0.001
end
end
describe "train/3" do
test "trains on synthetic data and returns state with metrics" do
# Generate small synthetic dataset: 64 samples, 13 features
key = Nx.Random.key(42)
{features, key} = Nx.Random.uniform(key, shape: {64, 20}, type: :f32)
{targets, _key} = Nx.Random.uniform(key, shape: {64, 1}, type: :f32)
{trained_state, metrics} = Model.train(features, targets, epochs: 2, batch_size: 32)
assert %Axon.ModelState{} = trained_state
assert is_float(metrics.final_loss)
assert metrics.final_loss >= 0.0
end
end
describe "evaluate/3" do
test "returns rmse and r_squared" do
params = Model.init()
key = Nx.Random.key(42)
{features, key} = Nx.Random.uniform(key, shape: {32, 20}, type: :f32)
{targets, _key} = Nx.Random.uniform(key, shape: {32, 1}, type: :f32)
metrics = Model.evaluate(params, features, targets)
assert is_float(metrics.rmse)
assert metrics.rmse >= 0.0
assert is_float(metrics.r_squared)
end
end
describe "predict_score/3" do
test "returns integer between 0 and 100" do
params = Model.init()
predict_fn = Model.compile_predict()
score =
Model.predict_score(predict_fn, params, %{
surface_temp_c: 25.0,
surface_dewpoint_c: 15.0,
surface_pressure_mb: 1015.0,
min_refractivity_gradient: -80.0,
hpbl_m: 600.0,
pwat_mm: 25.0,
utc_hour: 18,
month: 7,
freq_mhz: 10_000
})
assert is_integer(score)
assert score >= 0
assert score <= 100
end
test "returns different scores for different conditions" do
params = Model.init()
predict_fn = Model.compile_predict()
score_hot =
Model.predict_score(predict_fn, params, %{
surface_temp_c: 35.0,
surface_dewpoint_c: 25.0,
surface_pressure_mb: 1010.0,
min_refractivity_gradient: -300.0,
hpbl_m: 200.0,
pwat_mm: 40.0,
utc_hour: 3,
month: 7,
freq_mhz: 10_000
})
score_cold =
Model.predict_score(predict_fn, params, %{
surface_temp_c: -10.0,
surface_dewpoint_c: -20.0,
surface_pressure_mb: 1030.0,
min_refractivity_gradient: -40.0,
hpbl_m: 1500.0,
pwat_mm: 5.0,
utc_hour: 14,
month: 1,
freq_mhz: 10_000
})
# With random init, scores likely differ (not guaranteed but very probable)
assert is_integer(score_hot)
assert is_integer(score_cold)
end
end
describe "feature_names/0" do
test "returns 20 feature names" do
assert length(Model.feature_names()) == 20
end
end
describe "explain_prediction/3" do
test "returns score and one contribution entry per feature" do
params = Model.init()
predict_fn = Model.compile_predict()
result =
Model.explain_prediction(predict_fn, params, %{
surface_temp_c: 25.0,
surface_dewpoint_c: 18.0,
surface_pressure_mb: 1013.0,
min_refractivity_gradient: -250.0,
hpbl_m: 800.0,
pwat_mm: 30.0,
surface_refractivity: 340.0,
latitude: 32.5,
longitude: -97.0,
sfi: 130.0,
kp_max: 2.0,
ducting_detected: true,
k_index: 25.0,
lifted_index: -2.0,
utc_hour: 23,
month: 7,
freq_mhz: 10_000
})
assert is_integer(result.score)
assert result.score >= 0 and result.score <= 100
assert length(result.contributions) == 20
Enum.each(result.contributions, fn c ->
assert is_atom(c.feature)
assert is_float(c.normalized) or is_integer(c.normalized)
assert is_float(c.sensitivity)
assert is_float(c.contribution)
end)
end
test "contributions are sorted by absolute contribution descending" do
params = Model.init()
predict_fn = Model.compile_predict()
result =
Model.explain_prediction(predict_fn, params, %{
surface_temp_c: 15.0,
surface_dewpoint_c: 5.0,
freq_mhz: 24_000
})
magnitudes = Enum.map(result.contributions, &abs(&1.contribution))
assert magnitudes == Enum.sort(magnitudes, :desc)
end
test "every emitted feature name matches feature_names/0" do
params = Model.init()
predict_fn = Model.compile_predict()
result = Model.explain_prediction(predict_fn, params, %{freq_mhz: 47_000})
emitted = result.contributions |> Enum.map(& &1.feature) |> Enum.sort()
expected = Enum.sort(Model.feature_names())
assert emitted == expected
end
test "perturbing a feature changes the predicted score" do
# Verify the sensitivity output is non-trivial: the model must
# actually move when at least one feature moves. With random init
# this is essentially guaranteed unless every weight collapses.
params = Model.init()
predict_fn = Model.compile_predict()
result =
Model.explain_prediction(predict_fn, params, %{
surface_temp_c: 20.0,
surface_dewpoint_c: 10.0,
surface_pressure_mb: 1013.0,
freq_mhz: 10_000
})
max_sensitivity = result.contributions |> Enum.map(&abs(&1.sensitivity)) |> Enum.max()
assert max_sensitivity > 0.0
end
end
end