Merge pull request #60 from michaeldickens/fix-pareto-sample

Fix pareto_sample to sample from Pareto dist instead of Lomax
rethinkpriorities · Dec 18, 2023 · eeb215c · eeb215c
2 parents 04a45ec + 116de90
commit eeb215c
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/squigglepy/samplers.py b/squigglepy/samplers.py
@@ -473,7 +473,9 @@ def pareto_sample(shape, samples=1):
     >>> pareto_sample(1)
     10.069666324736094
     """
-    return _simplify(_get_rng().pareto(shape, samples))
+    # Add 1 because Numpy's "pareto" sampler actually samples from a Lomax
+    # distribution
+    return _simplify(_get_rng().pareto(shape, samples) + 1)
 
 
 def uniform_sample(low, high, samples=1):

diff --git a/tests/test_samplers.py b/tests/test_samplers.py
@@ -365,7 +365,7 @@ def test_sample_gamma_passes_lclip_rclip():
 
 @patch.object(samplers, "_get_rng", Mock(return_value=FakeRNG()))
 def test_sample_pareto_default():
-    assert sample(pareto(10)) == 10
+    assert sample(pareto(10)) == 11
 
 
 @patch.object(samplers, "_get_rng", Mock(return_value=FakeRNG()))