rename log_gamma to calibration_log_gamma (#527)

Author: daniel-habermann

bayesflow/diagnostics/metrics/__init__.py

@@ -4,4 +4,4 @@
 from .expected_calibration_error import expected_calibration_error
 from .classifier_two_sample_test import classifier_two_sample_test
 from .model_misspecification import bootstrap_comparison, summary_space_comparison
-from .sbc import log_gamma
+from .calibration_log_gamma import calibration_log_gamma, gamma_null_distribution, gamma_discrepancy

bayesflow/diagnostics/metrics/sbc.py renamed to bayesflow/diagnostics/metrics/calibration_log_gamma.py

@@ -6,7 +6,7 @@
 from ...utils.dict_utils import dicts_to_arrays
 
 
-def log_gamma(
+def calibration_log_gamma(
     estimates: Mapping[str, np.ndarray] | np.ndarray,
     targets: Mapping[str, np.ndarray] | np.ndarray,
     variable_keys: Sequence[str] = None,
@@ -15,7 +15,8 @@ def log_gamma(
     quantile: float = 0.05,
 ):
     """
-    Compute the log gamma discrepancy statistic, see [1] for additional information.
+    Compute the log gamma discrepancy statistic to test posterior calibration,
+    see [1] for additional information.
     Log gamma is log(gamma/gamma_null), where gamma_null is the 5th percentile of the
     null distribution under uniformity of ranks.
     That is, if adopting a hypothesis testing framework,then log_gamma < 0 implies

tests/test_diagnostics/test_diagnostics_metrics.py

@@ -85,15 +85,15 @@ def test_expected_calibration_error(pred_models, true_models, model_names):
         out = bf.diagnostics.metrics.expected_calibration_error(pred_models, true_models.transpose)
 
 
-def test_log_gamma(random_estimates, random_targets):
-    out = bf.diagnostics.metrics.log_gamma(random_estimates, random_targets)
+def test_calibration_log_gamma(random_estimates, random_targets):
+    out = bf.diagnostics.metrics.calibration_log_gamma(random_estimates, random_targets)
     assert list(out.keys()) == ["values", "metric_name", "variable_names"]
     assert out["values"].shape == (num_variables(random_estimates),)
     assert out["metric_name"] == "Log Gamma"
     assert out["variable_names"] == ["beta_0", "beta_1", "sigma"]
 
 
-def test_log_gamma_end_to_end():
+def test_calibration_log_gamma_end_to_end():
     # This is a function test for simulation-based calibration.
     # First, we sample from a known generative process and then run SBC.
     # If the log gamma statistic is correctly implemented, a 95% interval should exclude
@@ -116,11 +116,11 @@ def run_sbc(N=N, S=S, D=D, bias=0):
         ranks = np.sum(posterior_draws < prior_draws, axis=0)
 
         # this is the distribution of gamma under uniform ranks
-        gamma_null = bf.diagnostics.metrics.sbc.gamma_null_distribution(D, S, num_null_draws=100)
+        gamma_null = bf.diagnostics.metrics.gamma_null_distribution(D, S, num_null_draws=100)
         lower, upper = np.quantile(gamma_null, (0.05, 0.995))
 
         # this is the empirical gamma
-        observed_gamma = bf.diagnostics.metrics.sbc.gamma_discrepancy(ranks, num_post_draws=S)
+        observed_gamma = bf.diagnostics.metrics.gamma_discrepancy(ranks, num_post_draws=S)
 
         in_interval = lower <= observed_gamma < upper