ENH: Port PVsyst and Desoto parameter estimation from MATLAB

ci/requirements-py35.yml

@@ -23,6 +23,7 @@ dependencies:
     - scipy
     - shapely  # pvfactors dependency
     - siphon  # conda-forge
+    - statsmodels
     - pip:
         - nrel-pysam>=2.0
         - pvfactors==1.4.1

ci/requirements-py36.yml

@@ -25,6 +25,7 @@ dependencies:
     - scipy
     - shapely  # pvfactors dependency
     - siphon  # conda-forge
+    - statsmodels
     - pip:
         - nrel-pysam>=2.0
         - pvfactors==1.4.1

ci/requirements-py37.yml

@@ -25,6 +25,7 @@ dependencies:
     - scipy
     - shapely  # pvfactors dependency
     - siphon  # conda-forge
+    - statsmodels
     - pip:
         - nrel-pysam>=2.0
         - pvfactors==1.4.1

ci/requirements-py38.yml

@@ -25,6 +25,7 @@ dependencies:
     - scipy
     - shapely  # pvfactors dependency
     - siphon  # conda-forge
+    - statsmodels
     - pip:
         - nrel-pysam>=2.0
         - pvfactors==1.4.1

docs/sphinx/source/api.rst

@@ -314,6 +314,7 @@ Pvsyst model
 .. autosummary::
    :toctree: generated/
 
+   pvsystem.calcparams_pvsyst
    temperature.pvsyst_cell
    pvsystem.calcparams_pvsyst
    pvsystem.singlediode
@@ -328,6 +329,33 @@ PVWatts model
    inverter.pvwatts
    pvsystem.pvwatts_losses
 
+Estimating PV model parameters
+------------------------------
+
+Functions for fitting single diode models
+
+.. autosummary::
+   :toctree: generated/
+
+    ivtools.sdm.fit_cec_sam
+    ivtools.sdm.fit_desoto
+    ivtools.sdm.fit_pvsyst_sandia
+    ivtools.sdm.fit_desoto_sandia
+
+Functions for fitting the single diode equation
+
+.. autosummary::
+   :toctree: generated/
+
+    ivtools.sde.fit_sandia_simple
+
+Utilities for working with IV curve data
+
+.. autosummary::
+   :toctree: generated/
+
+    ivtools.utility.rectify_iv_curve
+
 Other
 -----
 

docs/sphinx/source/whatsnew/v0.8.0.rst

@@ -3,6 +3,17 @@
 v0.8.0 (Month day, year)
 -------------------------
 
+API Breaking Changes
+~~~~~~~~~~~~~~~~~~~~
+
+* The ``ivtools.py`` module has been reorganized into sub-modules and functions
+  in ``ivtools.py`` have been renamed (:pull:`708`)
+   - Functions for fitting diode models are now in ``ivtools\sdm.py``
+   - :py:func:`pvlib.ivtools.fit_sdm_cec_sam` is now :py:func:`pvlib.ivtools.sdm.fit_cec_sam`
+   - :py:func:`pvlib.ivtools.fit_sdm_desoto` is now :py:func:`pvlib.ivtools.sdm.fit_desoto`
+   - Functions for fitting the single diode equation are now in ``ivtools\sde.py``
+   - :py:func:`pvlib.ivtools.fit_sde_sandia` is now :py:func:`pvlib.ivtools.sde.fit_sandia_simple`
+
 API Changes with Deprecations
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * Moved functions related to inverters from ``pvsystem.py`` to ``inverter.py``.
@@ -70,6 +81,8 @@ Enhancements
   (:pull:`1017`)
 * Add :py:func:`pvlib.inverter.fit_sandia` that fits the Sandia inverter model
   to a set of inverter efficiency curves. (:pull:`1011`)
+* Add :py:func:`pvlib.ivtools.sdm.fit_pvsyst_sandia` and :py:func:`pvlib.ivtools.sdm.fit_desoto_sandia`
+  for fitting the Pvsyst and De Soto models to IV curve data (:issue:`227`)(:pull:`708`)
 * Add factory methods :py:meth:`~pvlib.modelchain.ModelChain.with_pvwatts`
   :py:meth:`~pvlib.modelchain.ModelChain.with_sapm` to create ``ModelChain``
   objects configured for the respective modeling paradigms. The