Merge pull request astropy#10900 from pllim/min-python-3.7

MNT: Bump minversion of Python to 3.7 (also Scipy, PyYAML, Matplotlib)

.circleci/config.yml

@@ -12,14 +12,8 @@ jobs:
           command: |
               mkdir -p $HOME/.astropy/config/
               printf "unicode_output = True\nmax_width = 500" > $HOME/.astropy/config/astropy.cfg
-      # In addition to testing 32-bit, we also use the 3.6 and 3.7 builds to
+      # In addition to testing 32-bit, we also use the 3.7 builds to
       # test the ability to run the test suite in parallel.
-      - run:
-          name: Install dependencies for Python 3.6
-          command: /opt/python/cp36-cp36m/bin/pip install tox
-      - run:
-          name: Run tests for Python 3.6
-          command: /opt/python/cp36-cp36m/bin/python -m tox -e py36-test -- -n=4 --durations=50
       - run:
           name: Install dependencies for Python 3.7
           command: /opt/python/cp37-cp37m/bin/pip install tox
@@ -39,40 +33,6 @@ jobs:
           name: Run tests for Python 3.8
           command: /opt/python/cp38-cp38/bin/python -m tox -e py38-test-double
 
-  image-tests-mpl212:
-    docker:
-      - image: astropy/image-tests-py36-mpl212:1.10
-    steps:
-      - checkout
-      - run:
-          name: Install dependencies
-          command: pip install -e .[test] pytest-mpl
-      - run:
-          name: Force scipy upgrade
-          command: pip install scipy -U
-      - run:
-          name: Run tests
-          command: pytest -P visualization --remote-data=astropy --open-files --mpl --mpl-results-path=$PWD/results -W ignore:np.asscalar
-      - store_artifacts:
-          path: results
-
-  image-tests-mpl222:
-    docker:
-      - image: astropy/image-tests-py36-mpl222:1.10
-    steps:
-      - checkout
-      - run:
-          name: Install dependencies
-          command: pip install -e .[test] pytest-mpl
-      - run:
-          name: Force scipy upgrade
-          command: pip install scipy -U
-      - run:
-          name: Run tests
-          command: pytest -P visualization --remote-data=astropy --open-files --mpl --mpl-results-path=$PWD/results -W ignore:np.asscalar
-      - store_artifacts:
-          path: results
-
   image-tests-mpl302:
     docker:
       - image: astropy/image-tests-py37-mpl302:1.10
@@ -123,8 +83,6 @@ workflows:
   tests:
     jobs:
       - 32bit-and-parallel
-      - image-tests-mpl212
-      - image-tests-mpl222
       - image-tests-mpl302
       - image-tests-mpl310
       - image-tests-mpldev

.travis.yml

@@ -97,10 +97,10 @@ matrix:
         # that tests do not open and leave open any files. This has a performance
         # impact on running the tests, hence why it is not enabled by default.
         - language: python
-          python: 3.6
+          python: 3.7
           stage: Comprehensive tests
-          name: Python 3.6 with oldest supported version of all dependencies
-          env: TOXENV="py36-test-oldestdeps"
+          name: Python 3.7 with oldest supported version of all dependencies
+          env: TOXENV="py37-test-oldestdeps"
                TOXPOSARGS="--open-files"
 
         # Now try with all optional dependencies.

CHANGES.rst

@@ -8,7 +8,7 @@ astropy.modeling
 ^^^^^^^^^^^^^^^^
 
 - N-dimensional least-squares statistic and specific 1,2,3-D methods [#10670]
-  
+
 
 
 4.2 (unreleased)
@@ -294,6 +294,12 @@ astropy.table
 
 - Raise a TypeError when a scalar column is added to an unsized table. [#10476]
 
+- The order of columns when creating a table from a ``list`` of ``dict`` may be
+  changed. Previously, the order was alphabetical because the ``dict`` keys
+  were assumed to be in random order. Since Python 3.7, the keys are always in
+  order of insertion, so ``Table`` now uses the order of keys in the first row
+  to set the column order. To alphabetize the columns to match the previous
+  behavior, use ``t = t[sorted(t.colnames)]``. [#10900]
 
 astropy.tests
 ^^^^^^^^^^^^^
@@ -424,7 +430,15 @@ astropy.wcs
 Other Changes and Additions
 ---------------------------
 
-- Minimum version of supported Numpy is now 1.17. [#10664]
+- Minimum version of required Python is now 3.7. [#10900]
+
+- Minimum version of required Numpy is now 1.17. [#10664]
+
+- Minimum version of required Scipy is now 1.1. [#10900]
+
+- Minimum version of required PyYAML is now 3.13. [#10900]
+
+- Minimum version of required Matplotlib is now 3.0. [#10900]
 
 - The private ``_erfa`` module has been converted to its own package,
   ``pyerfa``, which is a required dependency for astropy, and can be imported

CONTRIBUTING.md

@@ -144,7 +144,7 @@ package.
 
 **Code Quality**
   * Are the [coding guidelines](https://docs.astropy.org/en/latest/development/codeguide.html) followed?
-  * Is the code compatible with Python >=3.6?
+  * Is the code compatible with Python >=3.7?
   * Are there dependencies other than the `astropy` core, the Python Standard
     Library, and NumPy 1.17.0 or later?
     * Is the package importable even if the C-extensions are not built?

astropy/__init__.py

@@ -12,16 +12,19 @@
 
 from .version import version as __version__
 
-__minimum_python_version__ = '3.6'
+__minimum_python_version__ = '3.7'
 __minimum_numpy_version__ = '1.17.0'
 __minimum_erfa_version__ = '1.7'
-__minimum_scipy_version__ = '0.18'
+__minimum_scipy_version__ = '1.1'
 # ASDF is an optional dependency, but this is the minimum version that is
 # compatible with Astropy when it is installed.
 __minimum_asdf_version__ = '2.6.0'
 # PyYAML is an optional dependency, but this is the minimum version that is
 # advertised to be supported.
-__minimum_yaml_version__ = '3.12'
+__minimum_yaml_version__ = '3.13'
+# Matplotlib is an optional dependency, but this is the minimum version that is
+# advertised to be supported.
+__minimum_matplotlib_version__ = '3.0'
 
 
 class UnsupportedPythonError(Exception):

astropy/coordinates/matching.py

@@ -212,7 +212,7 @@ def search_around_3d(coords1, coords2, distlimit, storekdtree='kdtree_3d'):
 
     Notes
     -----
-    This function requires `SciPy <https://www.scipy.org/>`_ (>=0.12.0)
+    This function requires `SciPy <https://www.scipy.org/>`_
     to be installed or it will fail.
 
     If you are using this function to search in a catalog for matches around
@@ -318,7 +318,7 @@ def search_around_sky(coords1, coords2, seplimit, storekdtree='kdtree_sky'):
 
     Notes
     -----
-    This function requires `SciPy <https://www.scipy.org/>`_ (>=0.12.0)
+    This function requires `SciPy <https://www.scipy.org/>`_
     to be installed or it will fail.
 
     In the current implementation, the return values are always sorted in the

astropy/coordinates/sky_coordinate.py

@@ -1343,7 +1343,7 @@ def search_around_sky(self, searcharoundcoords, seplimit):
 
         Notes
         -----
-        This method requires `SciPy <https://www.scipy.org/>`_ (>=0.12.0) to be
+        This method requires `SciPy <https://www.scipy.org/>`_ to be
         installed or it will fail.
 
         In the current implementation, the return values are always sorted in
@@ -1402,7 +1402,7 @@ def search_around_3d(self, searcharoundcoords, distlimit):
 
         Notes
         -----
-        This method requires `SciPy <https://www.scipy.org/>`_ (>=0.12.0) to be
+        This method requires `SciPy <https://www.scipy.org/>`_ to be
         installed or it will fail.
 
         In the current implementation, the return values are always sorted in

astropy/io/fits/util.py

@@ -26,13 +26,8 @@
 
 from astropy.utils.exceptions import AstropyUserWarning
 
-try:
-    # Support the Python 3.6 PathLike ABC where possible
-    from os import PathLike
-    path_like = (str, PathLike)
-except ImportError:
-    path_like = (str,)
-
+from os import PathLike
+path_like = (str, PathLike)
 
 cmp = lambda a, b: (a > b) - (a < b)
 

astropy/io/misc/yaml.py

@@ -19,7 +19,7 @@
 - `astropy.coordinates.EarthLocation`
 - `astropy.table.SerializedColumn`
 
-.. note:: This module requires PyYaml version 3.12 or later.
+.. note:: This module requires PyYaml version 3.13 or later.
 
 Example
 =======
@@ -71,10 +71,10 @@
 try:
     import yaml
 except ImportError:
-    raise ImportError('The PyYAML package is required for astropy.io.misc.yaml and must be 3.12 or later')
+    raise ImportError('The PyYAML package is required for astropy.io.misc.yaml and must be 3.13 or later')
 else:
-    if not minversion(yaml, '3.12'):
-        raise ImportError('The PyYAML package is required for astropy.io.misc.yaml and must be 3.12 or later')
+    if not minversion(yaml, '3.13'):
+        raise ImportError('The PyYAML package is required for astropy.io.misc.yaml and must be 3.13 or later')
 
 
 __all__ = ['AstropyLoader', 'AstropyDumper', 'load', 'load_all', 'dump']

astropy/modeling/functional_models.py

@@ -700,7 +700,7 @@ def evaluate(cls, r, amplitude, r_eff, n):
                 from scipy.special import gammaincinv
                 cls._gammaincinv = gammaincinv
             except ValueError:
-                raise ImportError('Sersic1D model requires scipy > 0.11.')
+                raise ImportError('Sersic1D model requires scipy.')
 
         return (amplitude * np.exp(
             -cls._gammaincinv(2 * n, 0.5) * ((r / r_eff) ** (1 / n) - 1)))
@@ -2125,7 +2125,7 @@ def evaluate(cls, x, y, amplitude, x_0, y_0, radius):
                 cls._rz = jn_zeros(1, 1)[0] / np.pi
                 cls._j1 = j1
             except ValueError:
-                raise ImportError('AiryDisk2D model requires scipy > 0.11.')
+                raise ImportError('AiryDisk2D model requires scipy.')
 
         r = np.sqrt((x - x_0) ** 2 + (y - y_0) ** 2) / (radius / cls._rz)
 
@@ -2438,7 +2438,7 @@ def evaluate(cls, x, y, amplitude, r_eff, n, x_0, y_0, ellip, theta):
                 from scipy.special import gammaincinv
                 cls._gammaincinv = gammaincinv
             except ValueError:
-                raise ImportError('Sersic2D model requires scipy > 0.11.')
+                raise ImportError('Sersic2D model requires scipy.')
 
         bn = cls._gammaincinv(2. * n, 0.5)
         a, b = r_eff, (1 - ellip) * r_eff

astropy/modeling/tabular.py

@@ -22,18 +22,14 @@
 import numpy as np
 
 from astropy import units as u
-from astropy.utils import minversion
 from .core import Model
 
 try:
-    import scipy
     from scipy.interpolate import interpn
     has_scipy = True
 except ImportError:
     has_scipy = False
 
-has_scipy = has_scipy and minversion(scipy, "0.14")
-
 __all__ = ['tabular_model', 'Tabular1D', 'Tabular2D']
 
 __doctest_requires__ = {('tabular_model'): ['scipy']}
@@ -216,7 +212,7 @@ def evaluate(self, *inputs):
         inputs = [inp.flatten() for inp in inputs[: self.n_inputs]]
         inputs = np.array(inputs).T
         if not has_scipy:  # pragma: no cover
-            raise ImportError("This model requires scipy >= v0.14")
+            raise ImportError("Tabular model requires scipy.")
         result = interpn(self.points, self.lookup_table, inputs,
                          method=self.method, bounds_error=self.bounds_error,
                          fill_value=self.fill_value)

astropy/stats/funcs.py

@@ -1098,19 +1098,13 @@ def _scipy_kraft_burrows_nousek(N, B, CL):
 
     from scipy.optimize import brentq
     from scipy.integrate import quad
+    from scipy.special import factorial
 
     from math import exp
 
     def eqn8(N, B):
         n = np.arange(N + 1, dtype=np.float64)
-        # Create an array containing the factorials. scipy.special.factorial
-        # requires SciPy 0.14 (#5064) therefore this is calculated by using
-        # numpy.cumprod. This could be replaced by factorial again as soon as
-        # older SciPy are not supported anymore but the cumprod alternative
-        # might also be a bit faster.
-        factorial_n = np.ones(n.shape, dtype=np.float64)
-        np.cumprod(n[1:], out=factorial_n[1:])
-        return 1. / (exp(-B) * np.sum(np.power(B, n) / factorial_n))
+        return 1. / (exp(-B) * np.sum(np.power(B, n) / factorial(n)))
 
     # The parameters of eqn8 do not vary between calls so we can calculate the
     # result once and reuse it. The same is True for the factorial of N.

astropy/table/table.py

@@ -887,12 +887,7 @@ def _init_from_list_of_dicts(self, data, names, dtype, n_cols, copy):
         for row in data:
             names_from_data.update(row)
 
-        # Put names into a preferred order, either using the first row of data
-        # if it is ordered, or alphabetically.  Starting with Python 3.7, dict
-        # is ordered so this test can be relaxed.  (In practice CPython 3.6 is
-        # this way, but not according to the formal spec).
-        if (isinstance(data[0], OrderedDict)
-                and set(data[0].keys()) == names_from_data):
+        if set(data[0].keys()) == names_from_data:
             names_from_data = list(data[0].keys())
         else:
             names_from_data = sorted(names_from_data)

astropy/table/tests/test_init_table.py

@@ -546,8 +546,10 @@ def test_init_from_row_OrderedDict(table_type):
     rows34 = [row3, row4]
     t1 = table_type(rows=rows12)
     t2 = table_type(rows=rows34)
+    t3 = t2[sorted(t2.colnames)]
     assert t1.colnames == ['b', 'a']
-    assert t2.colnames == ['a', 'b']
+    assert t2.colnames == ['b', 'a']
+    assert t3.colnames == ['a', 'b']
 
 
 def test_init_from_rows_as_generator():

astropy/tests/helper.py

@@ -143,7 +143,7 @@ def __exit__(self, *exc_info):
         # https://github.com/astropy/astropy/pull/7372
         (r"Importing from numpy\.testing\.decorators is deprecated, "
          r"import from numpy\.testing instead\.", DeprecationWarning),
-        # inspect raises this slightly different warning on Python 3.6-3.7.
+        # inspect raises this slightly different warning on Python 3.7.
         # Keeping it since e.g. lxml as of 3.8.0 is still calling getargspec()
         (r"inspect\.getargspec\(\) is deprecated, use "
          r"inspect\.signature\(\) or inspect\.getfullargspec\(\)",

astropy/units/quantity_helper/scipy_special.py

@@ -63,10 +63,6 @@ def get_scipy_special_helpers():
     import scipy.special as sps
     SCIPY_HELPERS = {}
     for name in dimensionless_to_dimensionless_sps_ufuncs:
-        # TODO: Revert https://github.com/astropy/astropy/pull/7219 when
-        #       astropy requires scipy>=0.18, and loggamma is guaranteed
-        #       to exist.
-        # See https://github.com/astropy/astropy/issues/7159
         ufunc = getattr(sps, name, None)
         if ufunc:
             SCIPY_HELPERS[ufunc] = helper_dimensionless_to_dimensionless

astropy/visualization/mpl_style.py

@@ -4,10 +4,12 @@
 # plotting style. It is no longer documented/recommended as of Astropy v3.0
 # but is kept here for backward-compatibility.
 
+from astropy import __minimum_matplotlib_version__
 from astropy.utils import minversion
 
 # This returns False if matplotlib cannot be imported
-MATPLOTLIB_GE_1_5 = minversion('matplotlib', '1.5')
+MATPLOTLIB = minversion('matplotlib', __minimum_matplotlib_version__)
+
 
 __all__ = ['astropy_mpl_style_1', 'astropy_mpl_style']
 
@@ -75,12 +77,13 @@
                '#188487',   # turquoise
                '#E24A33']   # orange
 
-if MATPLOTLIB_GE_1_5:
+if MATPLOTLIB:
     # This is a dependency of matplotlib, so should be present.
     from cycler import cycler
     astropy_mpl_style_1['axes.prop_cycle'] = cycler('color', color_cycle)
 else:
     astropy_mpl_style_1['axes.color_cycle'] = color_cycle
 
+
 astropy_mpl_style = astropy_mpl_style_1
 """The most recent version of the astropy plotting style."""

astropy/visualization/scripts/fits2bitmap.py

@@ -92,16 +92,9 @@ def fits2bitmap(filename, ext=0, out_fn=None, stretch='linear',
             out_fn = os.path.splitext(out_fn)[0]
         out_fn += '.png'
 
-    # need to explicitly define the output format due to a bug in
-    # matplotlib (<= 2.1), otherwise the format will always be PNG
+    # explicitly define the output format
     out_format = os.path.splitext(out_fn)[1][1:]
 
-    # workaround for matplotlib 2.0.0 bug where png images are inverted
-    # (mpl-#7656)
-    if (out_format.lower() == 'png' and
-            matplotlib.__version__[:5] == '2.0.0'):
-        image = image[::-1]
-
     try:
         cm.get_cmap(cmap)
     except ValueError: