BUG: fix nan output of special.betaincinv (scipy#21678)

undefined
lobpcg · Oct 10, 2024 · 0396bdd · 0396bdd
1 parent 4ef4162
commit 0396bdd
Show file tree

Hide file tree

Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/scipy/_lib/boost_math b/scipy/_lib/boost_math
diff --git a/scipy/special/tests/test_basic.py b/scipy/special/tests/test_basic.py
@@ -1445,6 +1445,14 @@ def test_betainc_domain_errors(self, func, args):
             with pytest.raises(special.SpecialFunctionError, match='domain'):
                 special.betainc(*args)
 
+    @pytest.mark.parametrize('dtype', [np.float32, np.float64])
+    def test_gh21426(self, dtype):
+        # Test for gh-21426: betaincinv must not return NaN
+        a = np.array([5.], dtype=dtype)
+        x = np.array([0.5], dtype=dtype)
+        result = special.betaincinv(a, a, x)
+        assert_allclose(result, x, rtol=10 * np.finfo(dtype).eps)
+
 
 class TestCombinatorics:
     def test_comb(self):