Bump oldest supported numpy to 1.11. (matplotlib#12858)

Author: anntzer

.circleci/config.yml

@@ -134,7 +134,7 @@ jobs:
       - run:
           <<: *deps-install
           environment:
-            NUMPY_VERSION: "==1.10.0"
+            NUMPY_VERSION: "==1.11.0"
       - run: *mpl-install
 
       - run: *doc-build

INSTALL.rst

@@ -136,7 +136,7 @@ Matplotlib requires the following dependencies:
 * `Python <https://www.python.org/downloads/>`_ (>= 3.5)
 * `FreeType <https://www.freetype.org/>`_ (>= 2.3)
 * `libpng <http://www.libpng.org>`_ (>= 1.2)
-* `NumPy <http://www.numpy.org>`_ (>= 1.10.0)
+* `NumPy <http://www.numpy.org>`_ (>= 1.11)
 * `setuptools <https://setuptools.readthedocs.io/en/latest/>`_
 * `cycler <http://matplotlib.org/cycler/>`_ (>= 0.10.0)
 * `dateutil <https://pypi.org/project/python-dateutil>`_ (>= 2.1)

doc/api/next_api_changes/2018-11-22-AL.rst

@@ -0,0 +1,3 @@
+Numpy minimum version bump
+``````````````````````````
+Matplotlib 3.1 requires numpy>=1.11.

lib/matplotlib/__init__.py

@@ -191,7 +191,7 @@ def _check_versions():
             ("cycler", "0.10"),
             ("dateutil", "2.1"),
             ("kiwisolver", "1.0.1"),
-            ("numpy", "1.10"),
+            ("numpy", "1.11"),
             ("pyparsing", "2.0.1"),
     ]:
         module = importlib.import_module(modname)

lib/matplotlib/dates.py

@@ -254,10 +254,8 @@ def _dt64_to_ordinalf(d):
 
     # the "extra" ensures that we at least allow the dynamic range out to
     # seconds.  That should get out to +/-2e11 years.
-    # NOTE: First cast truncates; second cast back is for NumPy 1.10.
-    extra = d - d.astype('datetime64[s]').astype(d.dtype)
-    extra = extra.astype('timedelta64[ns]')
-    t0 = np.datetime64('0001-01-01T00:00:00').astype('datetime64[s]')
+    extra = (d - d.astype('datetime64[s]')).astype('timedelta64[ns]')
+    t0 = np.datetime64('0001-01-01T00:00:00', 's')
     dt = (d.astype('datetime64[s]') - t0).astype(np.float64)
     dt += extra.astype(np.float64) / 1.0e9
     dt = dt / SEC_PER_DAY + 1.0