Comparison with PVLIB_MATLAB

This document is under construction. Please see our PVSC 2014 paper and PVSC 2015 abstract for more information.

The pvlib-python license is BSD 3-clause, the PVLIB_MATLAB license is ??.

We want to keep developing the core functionality and algorithms of the Python and MATLAB projects roughly in parallel, but we’re not making any promises at this point. The PVLIB_MATLAB and pvlib-python projects are currently developed by different teams that do not regularly work together. We hope to grow this collaboration in the future. Do not expect feature parity between the libaries, only similarity.

Here are some of the major differences between the latest pvlib-python build and the original Sandia PVLIB_Python project, but many of these comments apply to the difference between pvlib-python and PVLIB_MATLAB.

Library wide changes

  • Remove pvl_ from module names.
  • Consolidation of similar modules. For example, functions from pvl_clearsky_ineichen.py and pvl_clearsky_haurwitz.py have been consolidated into clearsky.py.
  • Removed Vars=Locals(); Expect...; var=pvl\_tools.Parse(Vars,Expect); pattern. Very few tests of input validitity remain. Garbage in, garbage or nan out.
  • Removing unnecssary and sometimes undesired behavior such as setting maximum zenith=90 or airmass=0. Instead, we make extensive use of nan values.
  • Changing function and module names so that they do not conflict.
  • Added /pvlib/data for lookup tables, test, and tutorial data.
  • Added ‘’forecast.py’’ module, for downloading UNIDATA weather forecast data.

More specific changes

  • Add PyEphem option to solar position calculations.
  • irradiance.py has more AOI, projection, and irradiance sum and calculation functions
  • Locations are now pvlib.location.Location objects, not structs.
  • Specify time zones using a string from the standard IANA Time Zone Database naming conventions or using a pytz.timezone instead of an integer GMT offset. We may add dateutils support in the future.
  • clearsky.ineichen supports interpolating monthly Linke Turbidities to daily resolution.
  • Instead of requiring effective irradiance as an input, pvsystem.sapm calculates and returns it based on input POA irradiance, AM, and AOI.

Documentation

  • Using readthedocs for documentation hosting.
  • Many typos and formatting errors corrected.
  • Documentation source code and tutorials live in / rather than /pvlib/docs.
  • Additional tutorials in /docs/tutorials.

Testing

  • Tests are cleaner and more thorough. They are still no where near complete.
  • Using Coveralls to measure test coverage.
  • Using TravisCI for automated testing.
  • Using nosetests for more concise test code.