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| author | Charles Harris <charlesr.harris@gmail.com> | 2019-12-16 06:14:55 -0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-12-16 06:14:55 -0800 |
| commit | 2b03ae6f7ab945daeb6f9ae265dbfbbbe0b68f0b (patch) | |
| tree | ee33c0ceceb8fbb91390646e2b6658a146673a15 /numpy | |
| parent | bba2bd2012c6e1726e455c50995b685d12773c22 (diff) | |
| parent | 253084777f4b9aeb517253dbe5059fb90bf57a96 (diff) | |
| download | numpy-2b03ae6f7ab945daeb6f9ae265dbfbbbe0b68f0b.tar.gz | |
Merge pull request #15110 from tillahoffmann/expm1
MAINT: Fix expm1 instability for small complex numbers.
Diffstat (limited to 'numpy')
| -rw-r--r-- | numpy/core/src/umath/funcs.inc.src | 6 | ||||
| -rw-r--r-- | numpy/core/tests/test_umath.py | 6 |
2 files changed, 9 insertions, 3 deletions
diff --git a/numpy/core/src/umath/funcs.inc.src b/numpy/core/src/umath/funcs.inc.src index 10ed66e50..9c59cc8fb 100644 --- a/numpy/core/src/umath/funcs.inc.src +++ b/numpy/core/src/umath/funcs.inc.src @@ -360,9 +360,9 @@ nc_exp2@c@(@ctype@ *x, @ctype@ *r) static void nc_expm1@c@(@ctype@ *x, @ctype@ *r) { - @ftype@ a = npy_exp@c@(x->real); - r->real = a*npy_cos@c@(x->imag) - 1.0@c@; - r->imag = a*npy_sin@c@(x->imag); + @ftype@ a = npy_sin@c@(x->imag / 2); + r->real = npy_expm1@c@(x->real) * npy_cos@c@(x->imag) - 2 * a * a; + r->imag = npy_exp@c@(x->real) * npy_sin@c@(x->imag); return; } diff --git a/numpy/core/tests/test_umath.py b/numpy/core/tests/test_umath.py index e892e81d2..ae1090c23 100644 --- a/numpy/core/tests/test_umath.py +++ b/numpy/core/tests/test_umath.py @@ -888,6 +888,12 @@ class TestExpm1(object): assert_equal(ncu.expm1(np.inf), np.inf) assert_equal(ncu.expm1(-np.inf), -1.) + def test_complex(self): + x = np.asarray(1e-12) + assert_allclose(x, ncu.expm1(x)) + x = x.astype(np.complex128) + assert_allclose(x, ncu.expm1(x)) + class TestHypot(object): def test_simple(self): |