really fix the nan/dropped data problem in perez

Author: wholmgren

docs/tutorials/irradiance.ipynb

@@ -1106,19 +1106,17 @@ def perez(surface_tilt, surface_azimuth, dhi, dni, dni_extra,
     # delta is the sky's "brightness"
     delta = dhi * airmass / dni_extra
 
-    # keep only valid times
-    delta = delta[ebin.index]
-    z = z[ebin.index]
-
     # The various possible sets of Perez coefficients are contained
     # in a subfunction to clean up the code.
     F1c, F2c = _get_perez_coefficients(modelt)
 
-    F1 = F1c[ebin, 0] + F1c[ebin, 1] * delta + F1c[ebin, 2] * z
+    F1 = (F1c[ebin, 0] + F1c[ebin, 1] * delta[ebin.index] +
+          F1c[ebin, 2] * z[ebin.index])
     F1[F1 < 0] = 0
     F1 = F1.astype(float)
 
-    F2 = F2c[ebin, 0] + F2c[ebin, 1] * delta + F2c[ebin, 2] * z
+    F2 = (F2c[ebin, 0] + F2c[ebin, 1] * delta[ebin.index] +
+          F2c[ebin, 2] * z[ebin.index])
     F2[F2 < 0] = 0
     F2 = F2.astype(float)
 
@@ -1135,7 +1133,7 @@ def perez(surface_tilt, surface_azimuth, dhi, dni, dni_extra,
     term2 = F1 * A[ebin.index] / B[ebin.index]
     term3 = F2 * tools.sind(surface_tilt)
 
-    sky_diffuse = dhi[ebin.index] * (term1 + term2 + term3)
+    sky_diffuse = dhi * (term1 + term2 + term3)
     sky_diffuse[sky_diffuse < 0] = 0
     sky_diffuse[airmass.isnull()] = 0
 

pvlib/irradiance.py

@@ -1,8 +1,6 @@
 import logging
 pvl_logger = logging.getLogger('pvlib')
 
-import datetime
-
 import numpy as np
 import pandas as pd
 
@@ -20,12 +18,11 @@
 from . import requires_ephem
 
 # setup times and location to be tested.
-times = pd.date_range(start=datetime.datetime(2014, 6, 24),
-                      end=datetime.datetime(2014, 6, 26), freq='1Min')
-
 tus = Location(32.2, -111, 'US/Arizona', 700)
 
-times_localized = times.tz_localize(tus.tz)
+# must include night values
+times = pd.date_range(start='20140624', end='20140626', freq='1Min',
+                      tz=tus.tz)
 
 ephem_data = solarposition.get_solarposition(
     times, tus.latitude, tus.longitude, method='nrel_numpy')
@@ -145,7 +142,7 @@ def test_perez():
     out = irradiance.perez(40, 180, irrad_data['dhi'], irrad_data['dni'],
                      dni_et, ephem_data['apparent_zenith'],
                      ephem_data['azimuth'], am)
-    assert not out.isnull().all()
+    assert not out.isnull().any()
 
 # klutcher (misspelling) will be removed in 0.3
 def test_total_irrad():