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pvlib · cwhanse · Feb 23, 2024 · Feb 23, 2024 · Feb 23, 2024 · Feb 23, 2024
commit 464749e5d928149886854109f0bf838fa25c852b
diff --git a/docs/sphinx/source/whatsnew/v0.10.4.rst b/docs/sphinx/source/whatsnew/v0.10.4.rst
diff --git a/docs/sphinx/source/whatsnew/v0.10.5.rst b/docs/sphinx/source/whatsnew/v0.10.5.rst
@@ -11,7 +11,7 @@ Deprecations
 
 Enhancements
 ~~~~~~~~~~~~
-
+* Added a method to fit the Huld PV model (:pull:`1979`)
 
 Bug fixes
 ~~~~~~~~~

diff --git a/pvlib/pvarray.py b/pvlib/pvarray.py
@@ -427,10 +427,10 @@ def fit_huld(effective_irradiance, temp_module, pdc, method='ols'):
     gprime = effective_irradiance / 1000
     tprime = temp_module - 25
     # accomodate gprime<=0
+    logGprime = np.log(gprime, out=np.nan*gprime,
+                       where=np.array(gprime > 0))
     with np.errstate(divide='ignore'):
-        logGprime = np.log(gprime, out=np.zeros_like(gprime),
-                           where=np.array(gprime > 0))
-        Y = np.divide(pdc, gprime, out=np.zeros_like(gprime),
+        Y = np.divide(pdc, gprime, out=np.nan*gprime,
                       where=np.array(gprime > 0))
 
     X = np.stack((logGprime, logGprime**2, tprime, tprime*logGprime,

diff --git a/pvlib/tests/test_pvarray.py b/pvlib/tests/test_pvarray.py
@@ -93,18 +93,13 @@ def test_fit_huld(method):
     pdc = pvarray.huld(ee, tc, pdc0, cell_type='csi')
     pdc[11] = np.nan
     m_pdc0, k = pvarray.fit_huld(ee, tc, pdc, method='ols')
-    # known solution for OLS obtained with statsmodels v0.14.0
-    expected = np.array([2.07118648e+02, -8.35033390e+01, -3.83844606e+01,
-                         2.75629738e+00,  1.87571414e+00, -2.86429730e-01,
-                         -6.00418853e-02])
+    expected = np.array([pdc0, ] + [v for v in k0], dtype=float)
     modeled = np.hstack((m_pdc0, k))
-    assert_allclose(expected, modeled, rtol=1e-5)
+    assert_allclose(expected, modeled, rtol=1e-8)
 
 
 @requires_statsmodels
 def test_fit_huld_method_error():
-    # test is to recover the parameters in _infer_huld_k for each cell type
-    # IEC61853 conditions to make data for fitting
     ee, tc = pvarray._build_iec61853()
     pdc0 = 250
     pdc = pvarray.huld(ee, tc, pdc0, cell_type='csi')