Merge pull request #3726 from dcamron/analytic-satvap

Ambaum 2020 saturation vapor pressure + phase handling

Author: dopplershift

docs/conf.py

@@ -108,7 +108,8 @@
     ('py:class', r'.*TraitType'),
     ('py:class', r'.*object providing a view on.*'),  # Python dict docstring
     ('py:class', r'None.  .*'),  # Python dict docstring
-    ('py:class', r'.*D\[k\].*'),  # Python dict docstring
+    ('py:class', r'.*D\[k\].*'),  # Python dict docstring,
+    ('py:class', r"({'liquid'|'solid'|'auto'})")
 ]
 
 show_warning_types = True

src/metpy/calc/thermo.py

@@ -129,4 +129,37 @@ def broadcast_indices(indices, shape, axis):
     return tuple(ret)
 
 
+def validate_choice(options, /, **kwargs):
+    r"""Confirm that a choice is contained within a set of options.
+
+    Parameters
+    ----------
+    options : iterable
+
+    \*\*kwargs
+        Function kwarg names (keys) and their passed-in values (values) for validation
+
+    Raises
+    ------
+    ValueError
+        If the choice is not contained within any of these options, present valid options
+
+    Examples
+    --------
+    >>> from metpy.cbook import validate_choice
+    >>> def try_wrong_choice(color=None):
+    ...    validate_choice({'blue', 'green', 'yellow'}, color=color)
+    >>> try_wrong_choice(color='red') # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+    ValueError: 'red' is not a valid option for color.
+    Valid options are 'yellow', 'green', 'blue'.
+    """
+    for kw, choice in kwargs.items():
+        if choice not in options:
+            raise ValueError(
+                f'{choice!r} is not a valid option for {kw}. '
+                f'Valid options are {", ".join(map(repr, options))}.'
+            )
+
+
 __all__ = ('Registry', 'broadcast_indices', 'get_test_data')

src/metpy/cbook.py

@@ -21,7 +21,7 @@ def test_precipitable_water():
     """Test precipitable water with observed sounding."""
     data = get_upper_air_data(datetime(2016, 5, 22, 0), 'DDC')
     pw = precipitable_water(data['pressure'], data['dewpoint'], top=400 * units.hPa)
-    truth = 22.60430651 * units.millimeters
+    truth = 22.58809193 * units.millimeters
     assert_array_almost_equal(pw, truth, 4)
 
 
@@ -32,7 +32,7 @@ def test_precipitable_water_no_bounds():
     pressure = data['pressure']
     inds = pressure >= 400 * units.hPa
     pw = precipitable_water(pressure[inds], dewpoint[inds])
-    truth = 22.60430651 * units.millimeters
+    truth = 22.58809193 * units.millimeters
     assert_array_almost_equal(pw, truth, 4)
 
 
@@ -43,7 +43,7 @@ def test_precipitable_water_bound_error():
     dewpoint = np.array([25.5, 24.1, 23.1, 21.2, 21.1, 19.4, 19.2, 19.2, -87.1, -86.5, -86.5,
                          -86.5, -88.1]) * units.degC
     pw = precipitable_water(pressure, dewpoint)
-    truth = 89.86846252697836 * units('millimeters')
+    truth = 89.78451311253484 * units('millimeters')
     assert_almost_equal(pw, truth, 5)
 
 
@@ -59,7 +59,7 @@ def test_precipitable_water_nans():
                         -28.3, np.nan, -32.6, np.nan, -33.8, -35., -35.1, -38.1, -40.,
                         -43.3, -44.6, -46.4, -47., -49.2, -50.7]) * units.degC
     pw = precipitable_water(pressure, dewpoint)
-    truth = 4.003660322395436 * units.mm
+    truth = 3.997385016573651 * units.mm
     assert_almost_equal(pw, truth, 5)
 
 
@@ -161,7 +161,7 @@ def test_precipitable_water_xarray():
     press = xr.DataArray(data['pressure'].m, attrs={'units': str(data['pressure'].units)})
     dewp = xr.DataArray(data['dewpoint'], dims=('press',), coords=(press,))
     pw = precipitable_water(press, dewp, top=400 * units.hPa)
-    truth = 22.60430651 * units.millimeters
+    truth = 22.58809193 * units.millimeters
     assert_almost_equal(pw, truth)