Revert "Make tables a required dependency (pvlib#1287)"

This reverts commit 65782fd

Author: Hypfer

docs/sphinx/source/whatsnew/v0.9.0.rst

@@ -235,6 +235,7 @@ Requirements
 * ``dataclasses`` is required for python 3.6 (:pull:`1076`)
 * ``h5py`` is now a required dependency.  This replaces ``tables``, which was formerly
   an optional dependency.  (:pull:`1299`, :issue:`1252`, :issue:`1286`)
+* ``dataclasses`` is required for python 3.6
 
 Contributors
 ~~~~~~~~~~~~

pvlib/clearsky.py

@@ -194,15 +194,23 @@ def lookup_linke_turbidity(time, latitude, longitude, filepath=None,
     # 1st row: 89.9583 S, 2nd row: 89.875 S
     # 1st column: 179.9583 W, 2nd column: 179.875 W
 
+    try:
+        import tables
+    except ImportError:
+        raise ImportError('The Linke turbidity lookup table requires tables. '
+                          'You can still use clearsky.ineichen if you '
+                          'supply your own turbidities.')
+
     if filepath is None:
         pvlib_path = os.path.dirname(os.path.abspath(__file__))
         filepath = os.path.join(pvlib_path, 'data', 'LinkeTurbidities.h5')
 
     latitude_index = _degrees_to_index(latitude, coordinate='latitude')
     longitude_index = _degrees_to_index(longitude, coordinate='longitude')
 
-    with h5py.File(filepath, 'r') as lt_h5_file:
-        lts = lt_h5_file['LinkeTurbidity'][latitude_index, longitude_index]
+    with tables.open_file(filepath) as lt_h5_file:
+        lts = lt_h5_file.root.LinkeTurbidity[latitude_index,
+                                             longitude_index, :]
 
     if interp_turbidity:
         linke_turbidity = _interpolate_turbidity(lts, time)
@@ -290,6 +298,67 @@ def _calendar_month_middles(year):
     return middles
 
 
+def _degrees_to_index(degrees, coordinate):
+    """Transform input degrees to an output index integer. The Linke
+    turbidity lookup tables have three dimensions, latitude, longitude, and
+    month. Specify a degree value and either 'latitude' or 'longitude' to get
+    the appropriate index number for the first two of these index numbers.
+
+    Parameters
+    ----------
+    degrees : float or int
+        Degrees of either latitude or longitude.
+    coordinate : string
+        Specify whether degrees arg is latitude or longitude. Must be set to
+        either 'latitude' or 'longitude' or an error will be raised.
+
+    Returns
+    -------
+    index : np.int16
+        The latitude or longitude index number to use when looking up values
+        in the Linke turbidity lookup table.
+    """
+    # Assign inputmin, inputmax, and outputmax based on degree type.
+    if coordinate == 'latitude':
+        inputmin = 90
+        inputmax = -90
+        outputmax = 2160
+    elif coordinate == 'longitude':
+        inputmin = -180
+        inputmax = 180
+        outputmax = 4320
+    else:
+        raise IndexError("coordinate must be 'latitude' or 'longitude'.")
+
+    inputrange = inputmax - inputmin
+    scale = outputmax/inputrange  # number of indices per degree
+    center = inputmin + 1 / scale / 2  # shift to center of index
+    outputmax -= 1  # shift index to zero indexing
+    index = (degrees - center) * scale
+    err = IndexError('Input, %g, is out of range (%g, %g).' %
+                     (degrees, inputmin, inputmax))
+
+    # If the index is still out of bounds after rounding, raise an error.
+    # 0.500001 is used in comparisons instead of 0.5 to allow for a small
+    # margin of error which can occur when dealing with floating point numbers.
+    if index > outputmax:
+        if index - outputmax <= 0.500001:
+            index = outputmax
+        else:
+            raise err
+    elif index < 0:
+        if -index <= 0.500001:
+            index = 0
+        else:
+            raise err
+    # If the index wasn't set to outputmax or 0, round it and cast it as an
+    # integer so it can be used in integer-based indexing.
+    else:
+        index = int(np.around(index))
+
+    return index
+
+
 def haurwitz(apparent_zenith):
     '''
     Determine clear sky GHI using the Haurwitz model.

pvlib/tests/conftest.py

@@ -118,6 +118,15 @@ def assert_frame_equal(left, right, **kwargs):
     not has_statsmodels, reason='requires statsmodels')
 
 
+try:
+    import tables
+    has_tables = True
+except ImportError:
+    has_tables = False
+
+requires_tables = pytest.mark.skipif(not has_tables, reason='requires tables')
+
+
 try:
     import ephem  # noqa: F401
     has_ephem = True

pvlib/tests/test_clearsky.py

@@ -16,7 +16,7 @@
 from pvlib import atmosphere
 from pvlib import irradiance
 
-from .conftest import DATA_DIR
+from .conftest import requires_tables, DATA_DIR
 
 
 def test_ineichen_series():
@@ -189,6 +189,7 @@ def test_ineichen_altitude():
     assert_frame_equal(expected, out)
 
 
+@requires_tables
 def test_lookup_linke_turbidity():
     times = pd.date_range(start='2014-06-24', end='2014-06-25',
                           freq='12h', tz='America/Phoenix')
@@ -201,6 +202,7 @@ def test_lookup_linke_turbidity():
     assert_series_equal(expected, out)
 
 
+@requires_tables
 def test_lookup_linke_turbidity_leapyear():
     times = pd.date_range(start='2016-06-24', end='2016-06-25',
                           freq='12h', tz='America/Phoenix')
@@ -213,6 +215,7 @@ def test_lookup_linke_turbidity_leapyear():
     assert_series_equal(expected, out)
 
 
+@requires_tables
 def test_lookup_linke_turbidity_nointerp():
     times = pd.date_range(start='2014-06-24', end='2014-06-25',
                           freq='12h', tz='America/Phoenix')
@@ -223,6 +226,7 @@ def test_lookup_linke_turbidity_nointerp():
     assert_series_equal(expected, out)
 
 
+@requires_tables
 def test_lookup_linke_turbidity_months():
     times = pd.date_range(start='2014-04-01', end='2014-07-01',
                           freq='1M', tz='America/Phoenix')
@@ -233,6 +237,7 @@ def test_lookup_linke_turbidity_months():
     assert_series_equal(expected, out)
 
 
+@requires_tables
 def test_lookup_linke_turbidity_months_leapyear():
     times = pd.date_range(start='2016-04-01', end='2016-07-01',
                           freq='1M', tz='America/Phoenix')
@@ -243,6 +248,7 @@ def test_lookup_linke_turbidity_months_leapyear():
     assert_series_equal(expected, out)
 
 
+@requires_tables
 def test_lookup_linke_turbidity_nointerp_months():
     times = pd.date_range(start='2014-04-10', end='2014-07-10',
                           freq='1M', tz='America/Phoenix')
@@ -474,6 +480,7 @@ def test_simplified_solis_nans_series():
     assert_frame_equal(expected, out)
 
 
+@requires_tables
 def test_linke_turbidity_corners():
     """Test Linke turbidity corners out of bounds."""
     months = pd.DatetimeIndex('%d/1/2016' % (m + 1) for m in range(12))

pvlib/tests/test_location.py

@@ -16,7 +16,7 @@
 from pvlib.location import Location, lookup_altitude
 from pvlib.solarposition import declination_spencer71
 from pvlib.solarposition import equation_of_time_spencer71
-from .conftest import requires_ephem
+from .conftest import requires_ephem, requires_tables
 
 
 def test_location_required():
@@ -78,6 +78,7 @@ def times():
                          freq='3h')
 
 
+@requires_tables
 def test_get_clearsky(mocker, times):
     tus = Location(32.2, -111, 'US/Arizona', 700, 'Tucson')
     m = mocker.spy(pvlib.clearsky, 'ineichen')

pvlib/tests/test_modelchain.py

@@ -12,7 +12,7 @@
 from .conftest import assert_series_equal, assert_frame_equal
 import pytest
 
-from .conftest import fail_on_pvlib_version
+from .conftest import fail_on_pvlib_version, requires_tables
 
 
 @pytest.fixture(scope='function')
@@ -1787,6 +1787,72 @@ def test_ModelChain_no_extra_kwargs(sapm_dc_snl_ac_system, location):
         ModelChain(sapm_dc_snl_ac_system, location, arbitrary_kwarg='value')
 
 
+@fail_on_pvlib_version('0.10')
+def test_ModelChain_attributes_deprecated_10(sapm_dc_snl_ac_system, location):
+    match = 'Use ModelChain.results'
+    mc = ModelChain(sapm_dc_snl_ac_system, location)
+    with pytest.warns(pvlibDeprecationWarning, match=match):
+        mc.aoi
+    with pytest.warns(pvlibDeprecationWarning, match=match):
+        mc.aoi = 5
+
+
+@requires_tables
+def test_basic_chain_alt_az(sam_data, cec_inverter_parameters,
+                            sapm_temperature_cs5p_220m):
+    times = pd.date_range(start='20160101 1200-0700',
+                          end='20160101 1800-0700', freq='6H')
+    latitude = 32.2
+    longitude = -111
+    surface_tilt = 0
+    surface_azimuth = 0
+    modules = sam_data['sandiamod']
+    module_parameters = modules['Canadian_Solar_CS5P_220M___2009_']
+    temp_model_params = sapm_temperature_cs5p_220m.copy()
+    dc, ac = modelchain.basic_chain(times, latitude, longitude,
+                                    surface_tilt, surface_azimuth,
+                                    module_parameters, temp_model_params,
+                                    cec_inverter_parameters)
+
+    expected = pd.Series(np.array([111.621405, -2.00000000e-02]),
+                         index=times)
+    assert_series_equal(ac, expected)
+
+
+@requires_tables
+def test_basic_chain_altitude_pressure(sam_data, cec_inverter_parameters,
+                                       sapm_temperature_cs5p_220m):
+    times = pd.date_range(start='20160101 1200-0700',
+                          end='20160101 1800-0700', freq='6H')
+    latitude = 32.2
+    longitude = -111
+    altitude = 700
+    surface_tilt = 0
+    surface_azimuth = 0
+    modules = sam_data['sandiamod']
+    module_parameters = modules['Canadian_Solar_CS5P_220M___2009_']
+    temp_model_params = sapm_temperature_cs5p_220m.copy()
+    dc, ac = modelchain.basic_chain(times, latitude, longitude,
+                                    surface_tilt, surface_azimuth,
+                                    module_parameters, temp_model_params,
+                                    cec_inverter_parameters,
+                                    pressure=93194)
+
+    expected = pd.Series(np.array([113.190045, -2.00000000e-02]),
+                         index=times)
+    assert_series_equal(ac, expected)
+
+    dc, ac = modelchain.basic_chain(times, latitude, longitude,
+                                    surface_tilt, surface_azimuth,
+                                    module_parameters, temp_model_params,
+                                    cec_inverter_parameters,
+                                    altitude=altitude)
+
+    expected = pd.Series(np.array([113.189814, -2.00000000e-02]),
+                         index=times)
+    assert_series_equal(ac, expected)
+
+
 def test_complete_irradiance_clean_run(sapm_dc_snl_ac_system, location):
     """The DataFrame should not change if all columns are passed"""
     mc = ModelChain(sapm_dc_snl_ac_system, location)
@@ -1804,6 +1870,7 @@ def test_complete_irradiance_clean_run(sapm_dc_snl_ac_system, location):
                         pd.Series([9, 5], index=times, name='ghi'))
 
 
+@requires_tables
 def test_complete_irradiance(sapm_dc_snl_ac_system, location, mocker):
     """Check calculations"""
     mc = ModelChain(sapm_dc_snl_ac_system, location)
@@ -1836,6 +1903,7 @@ def test_complete_irradiance(sapm_dc_snl_ac_system, location, mocker):
 
 @pytest.mark.filterwarnings("ignore:This function is not safe at the moment")
 @pytest.mark.parametrize("input_type", [tuple, list])
+@requires_tables
 def test_complete_irradiance_arrays(
         sapm_dc_snl_ac_system_same_arrays, location, input_type):
     """ModelChain.complete_irradiance can accept a tuple of weather