Pvlib

-------------------------

API Changes
-------------------------
* `pvsystem.v_from_i` and `pvsystem.i_from_v` functions now accept
resistance_series = 0 and/or resistance_shunt = numpy.inf as inputs
(:issue:`340`)

Enhancements
-------------------------
* Improve clearsky.lookup_linke_turbidity speed. (:issue:`368`)
* Ideal devices supported in single diode model, e.g.,
resistance_series = 0 and/or resistance_shunt = numpy.inf (:issue:`340`)
* `pvsystem.v_from_i` and `pvsystem.i_from_v` computations for near ideal
devices are more numerically stable. However, very, very near ideal
resistance_series and/or resistance_shunt may still cause issues with the
implicit solver (:issue:`340`)

Bug fixes
-------------------------
* Remove condition causing Overflow warning from clearsky.haurwitz
(:issue:`363`)
* modelchain.basic_chain now correctly passes 'solar_position_method'
arg to solarposition.get_solarposition (:issue:`370`)
* Fixed: `Variables and Symbols extra references not available
<https://github.com/pvlib/pvlib-python/issues/380>`_ (:issue:`380`)
* Removed unnecessary calculations of alpha_prime in spa.solar_position_numpy
and spa.solar_position_loop (:issue:`366`)
* Fixed args mismatch for solarposition.pyephem call
from solarposition.get_solarposition with method='pyephem'
arg to solarposition.get_solarposition (:issue:`370`)
* ModelChain.prepare_inputs and ModelChain.complete_irradiance now
correctly pass the 'solar_position_method' argument to
solarposition.get_solarposition (:issue:`377`)
* Fixed usage of inplace parameter for tmy._recolumn (:issue:`342`)

Documentation
-------------------------
* Doc string of modelchain.basic_chain was updated to describe args
more accurately. (:issue:`370`)
* Doc strings of `singlediode`, `pvsystem.v_from_i`, and `pvsystem.i_from_v`
were updated to describe acceptable input arg ranges. (:issue:`340`)

Testing
-------------------------
* Changed test for clearsky.haurwitz to operate on zenith angles
* Significant new test cases added for `pvsystem.v_from_i` and
`pvsystem.i_from_v` (:issue:`340`)

Contributors
-------------------------
* Cliff Hansen
* KonstantinTr
* Will Holmgren
* Mark Campanelli
* DaCoEx

------------------------

API Changes
------------------------
* Removed parameter w from _calc_d (:issue:`344`)
* SingleAxisTracker.get_aoi and SingleAxisTracker.get_irradiance
now require surface_zenith and surface_azimuth (:issue:`351`)
* Changes calculation of the Incidence Angle Modifier to return 0
instead of np.nan for angles >= 90°. This improves the calculation of
effective irradiance close to sunrise and sunset. (:issue:`338`)
* Change the default ModelChain orientation strategy from
'south_at_latitude_tilt' to ``None``. (:issue:`290`)

Bug fixes
------------------------
* Method of multi-inheritance has changed to make it possible to use kwargs in
the parent classes of LocalizedPVSystem and LocalizedSingleAxisTracker
(:issue:`330`)
* Fix the `__repr__` method of `ModelChain`, crashing when
`orientation_strategy` is set to `'None'` (:issue:`352`)
* Fix the `ModelChain`'s angle of incidence calculation for
SingleAxisTracker objects (:issue:`351`)
* Fix issue with ForecastModel.cloud_cover_to_transmittance_linear method of
forecast.py ignoring 'offset' parameter. (:issue:`343`)

Enhancements
------------------------
* Added default values to docstrings of all functions (:issue:`336`)
* Added analytical method that calculates solar azimuth angle (:issue:`291`)

Documentation
------------------------
* Added ModelChain documentation page
* Added nbsphinx to documentation build configuration.
* Added a pull request template file (:issue:`354`)

Testing
------------------------
* Added explicit tests for aoi and aoi_projection functions.
* Update test of `ModelChain.__repr__` to take in account :issue:`352`
* Added a test for solar_azimuth_analytical function.

Contributors
------------------------
* Johannes Kaufmann
* Will Holmgren
* Uwe Krien
* Alaina Kafkes
* Birgit Schachler
* Jonathan Gaffiot
* Siyan (Veronica) Guo
* KonstantinTr

Bug fixes
---------

* Fix pandas 0.20 incompatibilities in Location.get_clearsky,
solarposition.ephemeris (:issue:`325`)
* Fixes timezone issue in solarposition spa_c function (:issue:`237`)
* Added NREL Bird clear sky model. (:issue:`276`)
* Added lower accuracy formulas for equation of time, declination, hour angle
and solar zenith.
* Remove all instances of .ix (:issue:`322`)
* Update docstring in `pvlib.spa.solar_position` - change units of pressure to
millibars. *NOTE*: units of pressure in `pvlib.solar_position.spa_python` and
`pvlib.solar_position.spa_c` are still Pascals. This update should have no
effect on most users, since it only applies to the low-level `spa.py` module.
(:issue:`327`)


Enhancements
----------------

* Added irradiance.dni method that determines DNI from GHI and DHI and corrects
unreasonable DNI values during sunrise/sunset transitions
* ForecastModel will now only connect to the Unidata server when necessary,
rather than when the object is created. This supports offline work
and speeds up analysis of previously downloaded data.


Contributors
-------------

* Will Holmgren
* Marc Anoma
* Mark Mikofski
* Birgit Schachler

Enhancements
- Added Anton Driesse Inverter database and made compatible with
pvsystem.retrieve_sam. (:issue:`169`)
- Ported Anton Driesse Inverter model from PV_LIB Toolbox. (:issue:`160`)
- Added Kasten pyrheliometric formula to calculate Linke turbidity factors with
improvements by Ineichen and Perez to extend range of air mass (:issue:`278`)
- Added coefficients for CIGS and a-Si modules types to the
first_solar_spectral_correction function (:issue:`308`)

API Changes
- Change PVSystem default module_parameters and inverter_parameters to
empty dict. Code that relied on these attributes being None or raising
a TypeError will need to be updated. (issue:`294`)

Documentation
- Fixes the Forecasting page's broken links to the tutorials.
- Fixes the Forecasting page's broken examples. (:issue:`299`)
- Fixes broken Classes link in the v0.3.0 documentation.

Bug fixes
- Resolved several issues with the forecast module tests. Library import
errors were resolved by prioritizing the conda-forge channel over the
default channel. Stalled ci runs were resolved by adding a timeout to
the HRRR_ESRL test. (:issue:`293`)
- Fixed issue with irradiance jupyter notebook tutorial. (:issue:`309`)

Contributors
- Will Holmgren
- Volker Beutner
- Mark Mikofski
- Anton Driesse
- Mitchell Lee

Enhancements
- Adding implementation of Perez's DIRINDEX model based on existing DIRINT
model implementation. (:issue:`282`)
- Added clearsky.detect_clearsky function to determine the clear times
in a GHI time series. (:issue:`284`)

Other
- Adds Python 3.6 to compatibility statement and pypi classifiers.
(:issue:`286`)

Contributors
- Marc Anoma
- Will Holmgren
- Cliff Hansen
- Tony Lorenzo

This is a minor release from 0.4.1.

Bug fixes
- Fixed typo in **repr** method of ModelChain and in its regarding test.
- PVSystem.pvwatts_ac could not use the eta_inv_ref kwarg and
PVSystem.pvwatts_dc could not use the temp_ref kwarg. Fixed. (:issue:`252`)
- Fixed typo in ModelChain.infer_spectral_model error message. (:issue:`251`)
- Fixed Linke turbdity factor out of bounds error at 90-degree latitude or at
180-degree longitude (:issue:`262`)
- Fixed Linke turbidity factor grid spacing and centers (:issue:`263`)

API Changes
- The run_model method of the ModelChain will use the weather parameter
of all weather data instead of splitting it to irradiation and weather.
The irradiation parameter still works but will be removed soon.
(:issue:`239`)
- delta_t kwarg is now 67.0 instead of None. IMPORTANT: Setting delta_t
as None will break the code for the Numba accelerated calculations.
This will be fixed in a future version. (:issue:`165`)

Enhancements
- Adding a complete_irradiance method to the ModelChain to make it
possible to calculate missing irradiation data from the existing
columns [beta]. (:issue:`239`)
- Added calculate_deltat method to the spa module to calculate the
time difference between terrestrial time and UT1. Specifying a scalar
is sufficient for most calculations. (:issue:`165`)
- Added more attributes to ModelChain, PVSystem, and Location printed
representations. (:issue:`254`)
- Added name attribute to ModelChain and PVSystem. (:issue:`254`)
- Restructured API section of the documentation so that there are
separate pages for each function, class, or method. (:issue:`258`)
- Improved Linke turbidity factor time interpolation with Python `calendar`
month days and leap years (:issue:`265`)
- Added option to return diffuse components from Perez transposition model.

Other
- Typical modeling results could change by ~1%, depending on location, if they
depend on the turbidity table
- Fixed issues with pvsystem, tracking, and tmy_to_power jupyter notebooks
(:issue:`267`, :issue:`273`)

Code Contributors
- Uwe Krien
- Will Holmgren
- Volker Beutner
- Mark Mikofski
- Marc Anoma
- Giuseppe Peronato