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

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lobpcg · Oct 10, 2024 · 0396bdd · 0396bdd
1 parent 4ef4162
commit 0396bdd
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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):