Merge pull request #1087 from jthielen/pint-0.9

Fix pint 0.9 errors from units.wraps and iterable

environment.yml

@@ -8,7 +8,7 @@ dependencies:
   - numpy
   - scipy
   - matplotlib
-  - pint!=0.9
+  - pint
   - netcdf4
   - xarray
   - pandas

metpy/cbook.py

@@ -6,7 +6,6 @@
 import os
 
 import numpy as np
-from numpy import iterable
 import pooch
 
 from . import __version__
@@ -102,4 +101,12 @@ def broadcast_indices(x, minv, ndim, axis):
     return tuple(ret)
 
 
+def iterable(value):
+    """Determine if value can be iterated over."""
+    # Special case for pint Quantities
+    if hasattr(value, 'magnitude'):
+        value = value.magnitude
+    return np.iterable(value)
+
+
 __all__ = ('Registry', 'broadcast_indices', 'get_test_data', 'is_string_like', 'iterable')

metpy/interpolate/one_dimension.py

@@ -10,7 +10,6 @@
 
 from ..cbook import broadcast_indices
 from ..package_tools import Exporter
-from ..units import units
 from ..xarray import preprocess_xarray
 
 exporter = Exporter(globals())
@@ -53,7 +52,6 @@ def interpolate_nans_1d(x, y, kind='linear'):
 
 @exporter.export
 @preprocess_xarray
-@units.wraps(None, ('=A', '=A'))
 def interpolate_1d(x, xp, *args, **kwargs):
     r"""Interpolates data with any shape over a specified axis.
 
@@ -100,6 +98,9 @@ def interpolate_1d(x, xp, *args, **kwargs):
     fill_value = kwargs.pop('fill_value', np.nan)
     axis = kwargs.pop('axis', 0)
 
+    # Handle units
+    x, xp = _strip_matching_units(x, xp)
+
     # Make x an array
     x = np.asanyarray(x).reshape(-1)
 
@@ -175,7 +176,6 @@ def interpolate_1d(x, xp, *args, **kwargs):
 
 @exporter.export
 @preprocess_xarray
-@units.wraps(None, ('=A', '=A'))
 def log_interpolate_1d(x, xp, *args, **kwargs):
     r"""Interpolates data with logarithmic x-scale over a specified axis.
 
@@ -222,7 +222,22 @@ def log_interpolate_1d(x, xp, *args, **kwargs):
     fill_value = kwargs.pop('fill_value', np.nan)
     axis = kwargs.pop('axis', 0)
 
+    # Handle units
+    x, xp = _strip_matching_units(x, xp)
+
     # Log x and xp
     log_x = np.log(x)
     log_xp = np.log(xp)
     return interpolate_1d(log_x, log_xp, *args, axis=axis, fill_value=fill_value)
+
+
+def _strip_matching_units(*args):
+    """Ensure arguments have same units and return with units stripped.
+
+    Replaces `@units.wraps(None, ('=A', '=A'))`, which breaks with `*args` handling for
+    pint>=0.9.
+    """
+    if all(hasattr(arr, 'units') for arr in args):
+        return [arr.to(args[0].units).magnitude for arr in args]
+    else:
+        return args

metpy/tests/test_units.py

@@ -8,6 +8,7 @@
 import matplotlib.pyplot as plt
 import numpy as np
 import pandas as pd
+import pint
 import pytest
 
 from metpy.testing import assert_array_almost_equal, assert_array_equal
@@ -35,6 +36,8 @@ def test_concatenate_masked():
     assert_array_equal(result.mask, np.array([False, True, False, False]))
 
 
+@pytest.mark.skipif(pint.__version__ == '0.9', reason=('Currently broken upstream (see '
+                                                       'pint#751'))
 @pytest.mark.mpl_image_compare(tolerance=0, remove_text=True)
 def test_axhline():
     r"""Ensure that passing a quantity to axhline does not error."""
@@ -45,6 +48,8 @@ def test_axhline():
     return fig
 
 
+@pytest.mark.skipif(pint.__version__ == '0.9', reason=('Currently broken upstream (see '
+                                                       'pint#751'))
 @pytest.mark.mpl_image_compare(tolerance=0, remove_text=True)
 def test_axvline():
     r"""Ensure that passing a quantity to axvline does not error."""

metpy/units.py

@@ -18,6 +18,7 @@
 
 import functools
 import logging
+import warnings
 
 import numpy as np
 import pint
@@ -46,6 +47,10 @@
 except AttributeError:
     log.warning('Failed to add gpm alias to meters.')
 
+# Silence UnitStrippedWarning
+if hasattr(pint, 'UnitStrippedWarning'):
+    warnings.simplefilter('ignore', category=pint.UnitStrippedWarning)
+
 
 def pandas_dataframe_to_unit_arrays(df, column_units=None):
     """Attach units to data in pandas dataframes and return united arrays.
@@ -317,7 +322,7 @@ def dec(func):
 try:
     # Try to enable pint's built-in support
     units.setup_matplotlib()
-except (AttributeError, RuntimeError):  # Pint's not available, try to enable our own
+except (AttributeError, RuntimeError, ImportError):  # Pint's not available, try our own
     import matplotlib.units as munits
 
     # Inheriting from object fixes the fact that matplotlib 1.4 doesn't

setup.py

@@ -51,7 +51,7 @@
 
     python_requires='>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*',
     install_requires=['matplotlib>=2.0.0', 'numpy>=1.12.0', 'scipy>=0.17.0',
-                      'pint!=0.9', 'xarray>=0.10.7', 'enum34;python_version<"3.4"',
+                      'pint', 'xarray>=0.10.7', 'enum34;python_version<"3.4"',
                       'contextlib2;python_version<"3.6"',
                       'pooch>=0.1', 'traitlets>=4.3.0'],
     extras_require={