diff options
| -rw-r--r-- | doc/release/upcoming_changes/16841.change.rst | 19 | ||||
| -rw-r--r-- | numpy/core/function_base.py | 8 | ||||
| -rw-r--r-- | numpy/core/tests/test_function_base.py | 5 |
3 files changed, 32 insertions, 0 deletions
diff --git a/doc/release/upcoming_changes/16841.change.rst b/doc/release/upcoming_changes/16841.change.rst new file mode 100644 index 000000000..d9499b6f4 --- /dev/null +++ b/doc/release/upcoming_changes/16841.change.rst @@ -0,0 +1,19 @@ +`np.linspace` on integers now use floor +--------------------------------------- +When using a `int` dtype in `numpy.linspace`, previously float values would +be rounded towards zero. Now `numpy.floor` is used instead, which rounds toward +``-inf``. This changes the results for negative values. For example, the +following would previously give:: + + >>> np.linspace(-3, 1, 8, dtype=int) + array([-3, -2, -1, -1, 0, 0, 0, 1]) + +and now results in:: + + >>> np.linspace(-3, 1, 8, dtype=int) + array([-3, -3, -2, -2, -1, -1, 0, 1]) + +The former result can still be obtained with:: + + >>> np.linspace(-3, 1, 8).astype(int) + array([-3, -2, -1, -1, 0, 0, 0, 1]) diff --git a/numpy/core/function_base.py b/numpy/core/function_base.py index f57e95742..b2f17cfeb 100644 --- a/numpy/core/function_base.py +++ b/numpy/core/function_base.py @@ -34,6 +34,11 @@ def linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None, .. versionchanged:: 1.16.0 Non-scalar `start` and `stop` are now supported. + .. versionchanged:: 1.20.0 + Values are rounded towards ``-inf`` instead of ``0`` when an + integer ``dtype`` is specified. The old behavior can + still be obtained with ``np.linspace(start, stop, num).astype(int)`` + Parameters ---------- start : array_like @@ -160,6 +165,9 @@ def linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None, if axis != 0: y = _nx.moveaxis(y, 0, axis) + + if _nx.issubdtype(dtype, _nx.integer): + _nx.floor(y, out=y) if retstep: return y.astype(dtype, copy=False), step diff --git a/numpy/core/tests/test_function_base.py b/numpy/core/tests/test_function_base.py index 62a9772c8..dad7a5883 100644 --- a/numpy/core/tests/test_function_base.py +++ b/numpy/core/tests/test_function_base.py @@ -402,3 +402,8 @@ class TestLinspace: stop = array(2, dtype='O') y = linspace(start, stop, 3) assert_array_equal(y, array([1., 1.5, 2.])) + + def test_round_negative(self): + y = linspace(-1, 3, num=8, dtype=int) + t = array([-1, -1, 0, 0, 1, 1, 2, 3], dtype=int) + assert_array_equal(y, t) |