Simplify Numba usage; numba-fy temperature.fuentes

benchmarks/benchmarks/solarposition.py

@@ -4,11 +4,15 @@
 
 import datetime
 import pandas as pd
-import pvlib
-from pvlib import solarposition
-
 from pkg_resources import parse_version
 
+# Numba is installed in the benchmark environments, but we'll disable it here.
+# so pvlib will switch to numpy functions (see NUMBA_ACTIVE in pvlib.tools).
+import numba
+numba.config.DISABLE_JIT = 1
+import pvlib  # NOQA: E402
+from pvlib import solarposition  # NOQA: E402
+
 
 if parse_version(pvlib.__version__) >= parse_version('0.6.1'):
     sun_rise_set_transit_spa = solarposition.sun_rise_set_transit_spa

benchmarks/benchmarks/solarposition_numba.py

@@ -10,12 +10,8 @@
 from pkg_resources import parse_version
 import pandas as pd
 
-import os
-os.environ['PVLIB_USE_NUMBA'] = '1'
-
-
-import pvlib  # NOQA: E402
-from pvlib import solarposition  # NOQA: E402
+import pvlib
+from pvlib import solarposition
 
 
 if parse_version(pvlib.__version__) >= parse_version('0.6.1'):

ci/azure/conda_linux.yml

@@ -11,6 +11,8 @@ jobs:
       Python36-min:
         python.version: '36'
         suffix: '-min'
+        coverage: true  # report coverage for both 36 and 36-min to combine
+                        # coverage for both numba and non-numba codepaths
       Python36:
         python.version: '36'
         coverage: true

docs/sphinx/source/api.rst

@@ -1,3 +1,5 @@
+.. _api:
+
 .. currentmodule:: pvlib
 
 #############

docs/sphinx/source/installation.rst

@@ -270,6 +270,34 @@ To install the NREL SPA algorithm for use with pvlib:
 #. From the ``pvlib-python`` directory, run ``pip uninstall pvlib``
    followed by ``pip install .``
 
+
+.. _using_numba:
+
+Numba Acceleration
+------------------
+
+Some of the models offered by pvlib-python are difficult to implement
+using vectorized numpy code and instead use comparatively inefficient
+python code. To avoid the slowdown of using basic python, some functions
+in pvlib-python include optional JIT-compiling support through the
+`numba <https://numba.pydata.org/>`_ python package.  Installing numba
+is not required to run these functions, but it will improve the runtime
+of these functions significantly.  Functions that can be accelerated
+with numba have a corresponding note on their page in the :ref:`api`.
+
+By default, numba is used automatically if it is present in your
+python environment.  However, it can be disabled by using the
+``NUMBA_DISABLE_JIT`` environment variable.  The same can be accomplished
+by importing and configuring numba prior to importing pvlib, like this::
+
+    import numba
+    numba.config.DISABLE_JIT = 1
+    import pvlib
+
+For more details, see numba's
+`documentation <https://numba.pydata.org/numba-doc/dev/user/troubleshoot.html#disabling-jit-compilation>`_.
+
+
 .. _references:
 
 References

pvlib/modelchain.py

@@ -69,7 +69,7 @@ def basic_chain(times, latitude, longitude,
                 surface_tilt=None, surface_azimuth=None,
                 orientation_strategy=None,
                 transposition_model='haydavies',
-                solar_position_method='nrel_numpy',
+                solar_position_method='nrel',
                 airmass_model='kastenyoung1989',
                 altitude=None, pressure=None,
                 **kwargs):
@@ -132,7 +132,7 @@ def basic_chain(times, latitude, longitude,
     transposition_model : str, default 'haydavies'
         Passed to system.get_irradiance.
 
-    solar_position_method : str, default 'nrel_numpy'
+    solar_position_method : str, default 'nrel'
         Passed to solarposition.get_solarposition.
 
     airmass_model : str, default 'kastenyoung1989'
@@ -344,7 +344,7 @@ class ModelChain:
     transposition_model : str, default 'haydavies'
         Passed to system.get_irradiance.
 
-    solar_position_method : str, default 'nrel_numpy'
+    solar_position_method : str, default 'nrel'
         Passed to location.get_solarposition.
 
     airmass_model : str, default 'kastenyoung1989'
@@ -398,7 +398,7 @@ def __init__(self, system, location,
                  orientation_strategy=None,
                  clearsky_model='ineichen',
                  transposition_model='haydavies',
-                 solar_position_method='nrel_numpy',
+                 solar_position_method='nrel',
                  airmass_model='kastenyoung1989',
                  dc_model=None, ac_model=None, aoi_model=None,
                  spectral_model=None, temperature_model=None,
@@ -505,7 +505,7 @@ def with_pvwatts(cls, system, location,
           orientation_strategy: None
           clearsky_model: ineichen
           transposition_model: perez
-          solar_position_method: nrel_numpy
+          solar_position_method: nrel
           airmass_model: kastenyoung1989
           dc_model: pvwatts_dc
           ac_model: pvwatts_inverter
@@ -530,7 +530,7 @@ def with_sapm(cls, system, location,
                   orientation_strategy=None,
                   clearsky_model='ineichen',
                   transposition_model='haydavies',
-                  solar_position_method='nrel_numpy',
+                  solar_position_method='nrel',
                   airmass_model='kastenyoung1989',
                   name=None,
                   **kwargs):
@@ -560,7 +560,7 @@ def with_sapm(cls, system, location,
         transposition_model : str, default 'haydavies'
             Passed to system.get_irradiance.
 
-        solar_position_method : str, default 'nrel_numpy'
+        solar_position_method : str, default 'nrel'
             Passed to location.get_solarposition.
 
         airmass_model : str, default 'kastenyoung1989'
@@ -592,7 +592,7 @@ def with_sapm(cls, system, location,
           orientation_strategy: None
           clearsky_model: ineichen
           transposition_model: haydavies
-          solar_position_method: nrel_numpy
+          solar_position_method: nrel
           airmass_model: kastenyoung1989
           dc_model: sapm
           ac_model: snlinverter