diff options
| -rw-r--r-- | numpy/ma/extras.py | 7 | ||||
| -rw-r--r-- | numpy/ma/tests/test_regression.py | 8 |
2 files changed, 11 insertions, 4 deletions
diff --git a/numpy/ma/extras.py b/numpy/ma/extras.py index 2f3159c49..5a484ce9d 100644 --- a/numpy/ma/extras.py +++ b/numpy/ma/extras.py @@ -1402,14 +1402,13 @@ def corrcoef(x, y=None, rowvar=True, bias=False, allow_masked=True, ddof=None): if rowvar: for i in range(n - 1): for j in range(i + 1, n): - _x = mask_cols(vstack((x[i], x[j]))).var(axis=1, - ddof=1 - bias) + _x = mask_cols(vstack((x[i], x[j]))).var(axis=1, ddof=ddof) _denom[i, j] = _denom[j, i] = ma.sqrt(ma.multiply.reduce(_x)) else: for i in range(n - 1): for j in range(i + 1, n): - _x = mask_cols(vstack((x[:, i], x[:, j]))).var(axis=1, - ddof=1 - bias) + _x = mask_cols( + vstack((x[:, i], x[:, j]))).var(axis=1, ddof=ddof) _denom[i, j] = _denom[j, i] = ma.sqrt(ma.multiply.reduce(_x)) return c / _denom diff --git a/numpy/ma/tests/test_regression.py b/numpy/ma/tests/test_regression.py index f713a8a1a..eb301aa05 100644 --- a/numpy/ma/tests/test_regression.py +++ b/numpy/ma/tests/test_regression.py @@ -61,6 +61,14 @@ class TestRegression(TestCase): a.var(out=mout) assert_(mout._data == 0) + def test_ddof_corrcoef(self): + # See gh-3336 + x = np.ma.masked_equal([1,2,3,4,5], 4) + y = np.array([2,2.5,3.1,3,5]) + r0 = np.ma.corrcoef(x, y, ddof=0) + r1 = np.ma.corrcoef(x, y, ddof=1) + # ddof should not have an effect (it gets cancelled out) + assert_allclose(r0.data, r1.data) if __name__ == "__main__": run_module_suite() |