.. _whatsnew_0420:

v0.4.2 (December 7, 2016)
-------------------------

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
