def test_simple(
train_window, min_train_window, test_window, min_test_window, stride, warm_start
):
duration = 30
obs_dim = 2
covariates = torch.zeros(duration, 0)
data = torch.randn(duration, obs_dim) + 4
forecaster_options = {"num_steps": 2, "warm_start": warm_start}
expect_error = warm_start and train_window is not None
with optional(pytest.raises(ValueError), expect_error):
windows = backtest(
data,
covariates,
Model,
train_window=train_window,
min_train_window=min_train_window,
test_window=test_window,
min_test_window=min_test_window,
stride=stride,
forecaster_options=forecaster_options,
)
if not expect_error:
assert any(window["t0"] == 0 for window in windows)
if stride == 1:
assert any(window["t2"] == duration for window in windows)
for window in windows:
assert window["train_walltime"] >= 0
assert window["test_walltime"] >= 0
for name in DEFAULT_METRICS:
assert name in window
assert 0 < window[name] < math.inf
def test_custom_warm_start():
duration = 30
obs_dim = 2
covariates = torch.zeros(duration, 0)
data = torch.randn(duration, obs_dim) + 4
min_train_window = 10
def forecaster_options(t0, t1, t2):
if t1 == min_train_window:
return {"num_steps": 2, "warm_start": True}
else:
return {"num_steps": 0, "warm_start": True}
backtest(data, covariates, Model,
min_train_window=min_train_window,
test_window=10,
forecaster_options=forecaster_options)
def test_poisson(
train_window, min_train_window, test_window, min_test_window, stride, engine
):
duration = 30
obs_dim = 2
covariates = torch.zeros(duration, 0)
rate = torch.randn(duration, obs_dim) + 4
counts = dist.Poisson(rate).sample()
# Transform count data to log domain.
data = counts.log1p()
def transform(pred, truth):
pred = dist.Poisson(pred.clamp(min=1e-4).expm1()).sample()
truth = truth.expm1()
return pred, truth
if engine == "svi":
forecaster_fn = Forecaster
forecaster_options = {"num_steps": 2}
else:
forecaster_fn = HMCForecaster
forecaster_options = {"num_warmup": 1, "num_samples": 1}
windows = backtest(
data,
covariates,
Model,
forecaster_fn=forecaster_fn,
transform=transform,
train_window=train_window,
min_train_window=min_train_window,
test_window=test_window,
min_test_window=min_test_window,
stride=stride,
forecaster_options=forecaster_options,
)
assert any(window["t0"] == 0 for window in windows)
if stride == 1:
assert any(window["t0"] == 0 for window in windows)
assert any(window["t2"] == duration for window in windows)
for name in DEFAULT_METRICS:
for window in windows:
assert name in window
assert 0 < window[name] < math.inf
def main(args):
data, covariates = preprocess(args)
# We will model positive count data by log1p-transforming it into real
# valued data. But since we want to evaluate back in the count domain, we
# will also define a transform to apply during evaluation, transforming
# from real back to count-valued data. Truth is mapped by the log1p()
# inverse expm1(), but the prediction will be sampled from a Poisson
# distribution.
data = data.log1p()
def transform(pred, truth):
pred = torch.poisson(pred.clamp(min=1e-4).expm1())
truth = truth.expm1()
return pred, truth
# The backtest() function automatically trains and evaluates our model on
# different windows of data.
forecaster_options = {
"num_steps": args.num_steps,
"learning_rate": args.learning_rate,
"log_every": args.log_every,
"dct_gradients": args.dct,
}
metrics = backtest(
data,
covariates,
Model,
train_window=args.train_window,
test_window=args.test_window,
stride=args.stride,
num_samples=args.num_samples,
forecaster_options=forecaster_options,
)
for name in ["mae", "rmse", "crps"]:
values = [m[name] for m in metrics]
mean = np.mean(values)
std = np.std(values)
print("{} = {:0.3g} +- {:0.3g}".format(name, mean, std))
return metrics
