Make sapm iam function use common interface

Author: markcampanelli

pvlib/iam.py

@@ -17,7 +17,7 @@
 from pvlib.tools import cosd, sind, acosd
 
 
-def get_builtin_models():
+def _get_builtin_models():
     """
     Get builtin IAM models' usage information.
 
@@ -66,8 +66,6 @@ def get_builtin_models():
         },
         'sapm': {
             'func': sapm,
-            # Exceptional interface: Parameters inside params_required must
-            # appear in the required module dictionary parameter.
             'params_required': {'B0', 'B1', 'B2', 'B3', 'B4', 'B5'},
             'params_optional': {'upper'},
         },
@@ -557,7 +555,7 @@ def interp(aoi, theta_ref, iam_ref, method='linear', normalize=True):
     return iam
 
 
-def sapm(aoi, module, upper=None):
+def sapm(aoi, B0, B1, B2, B3, B4, B5, upper=None):
     r"""
     Determine the incidence angle modifier (IAM) using the SAPM model.
 
@@ -567,9 +565,17 @@ def sapm(aoi, module, upper=None):
         Angle of incidence in degrees. Negative input angles will return
         zeros.
 
-    module : dict-like
-        A dict or Series with the SAPM IAM model parameters.
-        See the :py:func:`sapm` notes section for more details.
+    B0 : The coefficient of the degree-0 polynomial term.
+    
+    B1 : The coefficient of the degree-1 polynomial term.
+    
+    B2 : The coefficient of the degree-2 polynomial term.
+    
+    B3 : The coefficient of the degree-3 polynomial term.
+    
+    B4 : The coefficient of the degree-4 polynomial term.
+    
+    B5 : The coefficient of the degree-5 polynomial term.
 
     upper : float, optional
         Upper limit on the results. None means no upper limiting.
@@ -609,10 +615,7 @@ def sapm(aoi, module, upper=None):
     pvlib.iam.schlick
     """
 
-    aoi_coeff = [module['B5'], module['B4'], module['B3'], module['B2'],
-                 module['B1'], module['B0']]
-
-    iam = np.polyval(aoi_coeff, aoi)
+    iam = np.polyval([B5, B4, B3, B2, B1, B0], aoi)
     iam = np.clip(iam, 0, upper)
     # nan tolerant masking
     aoi_lt_0 = np.full_like(aoi, False, dtype='bool')
@@ -665,6 +668,7 @@ def marion_diffuse(model, surface_tilt, **kwargs):
     pvlib.iam.interp
     pvlib.iam.martin_ruiz
     pvlib.iam.physical
+    pvlib.iam.sapm
     pvlib.iam.schlick
     pvlib.iam.martin_ruiz_diffuse
     pvlib.iam.schlick_diffuse
@@ -693,7 +697,7 @@ def marion_diffuse(model, surface_tilt, **kwargs):
         func = model
     else:
         # Check that a builtin IAM function was specified.
-        builtin_models = get_builtin_models()
+        builtin_models = _get_builtin_models()
 
         try:
             model = builtin_models[model]
@@ -1035,7 +1039,7 @@ def _get_fittable_or_convertable_model(builtin_model_name):
 def _check_params(builtin_model_name, params):
     # check that parameters passed in with IAM model belong to the model
     handed_params = set(params.keys())
-    builtin_model = get_builtin_models()[builtin_model_name]
+    builtin_model = _get_builtin_models()[builtin_model_name]
     expected_params = builtin_model["params_required"].union(
         builtin_model["params_optional"]
     )

pvlib/modelchain.py

@@ -6,12 +6,13 @@
 the time to read the source code for the module.
 """
 
+from dataclasses import dataclass, field
 from functools import partial
 import itertools
+from typing import Optional, Tuple, TypeVar, Union
 import warnings
+
 import pandas as pd
-from dataclasses import dataclass, field
-from typing import Union, Tuple, Optional, TypeVar
 
 from pvlib import pvsystem
 import pvlib.irradiance  # avoid name conflict with full import
@@ -794,7 +795,7 @@ def infer_aoi_model(self):
             array.module_parameters for array in self.system.arrays
         )
         params = _common_keys(module_parameters)
-        builtin_models = pvlib.iam.get_builtin_models()
+        builtin_models = pvlib.iam._get_builtin_models()
 
         if any(
             param in params for

pvlib/pvsystem.py

@@ -1192,28 +1192,22 @@ def get_iam(self, aoi, iam_model='physical'):
         model = iam_model.lower()
 
         try:
-            model_info = iam.get_builtin_models()[model]
+            model_info = iam._get_builtin_models()[model]
         except KeyError as exc:
             raise ValueError(f'{iam_model} is not a valid iam_model') from exc
 
         for param in model_info["params_required"]:
             if param not in self.module_parameters:
                 raise KeyError(f"{param} is missing in module_parameters")
 
-        params_optional = _build_kwargs(
-            model_info["params_optional"], self.module_parameters
-        )
-
-        if model == "sapm":
-            # sapm has exceptional interface requiring module_parameters.
-            return model_info["func"](
-                aoi, self.module_parameters, **params_optional
-            )
-
         params_required = _build_kwargs(
             model_info["params_required"], self.module_parameters
         )
 
+        params_optional = _build_kwargs(
+            model_info["params_optional"], self.module_parameters
+        )
+
         return model_info["func"](
             aoi, **params_required, **params_optional
         )
@@ -2397,7 +2391,15 @@ def sapm_effective_irradiance(poa_direct, poa_diffuse, airmass_absolute, aoi,
     """
 
     F1 = spectrum.spectral_factor_sapm(airmass_absolute, module)
-    F2 = iam.sapm(aoi, module)
+    F2 = iam.sapm(
+        aoi,
+        module["B0"],
+        module["B1"],
+        module["B2"],
+        module["B3"],
+        module["B4"],
+        module["B5"],
+    )
 
     Ee = F1 * (poa_direct * F2 + module['FD'] * poa_diffuse)
 

pvlib/tests/test_iam.py

@@ -6,18 +6,17 @@
 import inspect
 
 import numpy as np
+from numpy.testing import assert_allclose
 import pandas as pd
-
 import pytest
-from .conftest import assert_series_equal
-from numpy.testing import assert_allclose
 import scipy.interpolate
 
 from pvlib import iam as _iam
+from pvlib.tests.conftest import assert_series_equal
 
 
 def test_get_builtin_models():
-    builtin_models = _iam.get_builtin_models()
+    builtin_models = _iam._get_builtin_models()
 
     models = set(builtin_models.keys())
     models_expected = {
@@ -28,26 +27,14 @@ def test_get_builtin_models():
     for model in models:
         builtin_model = builtin_models[model]
 
-        if model == "sapm":
-            # sapm has exceptional interface requiring module_parameters.
-            params_required_expected = set(
-                k for k, v in inspect.signature(
-                    builtin_model["func"]
-                ).parameters.items() if v.default is inspect.Parameter.empty
-            )
-            assert {"aoi", "module"} == params_required_expected, model
-
-            assert builtin_model["params_required"] == \
-                {'B0', 'B1', 'B2', 'B3', 'B4', 'B5'}, model
-        else:
-            params_required_expected = set(
-                k for k, v in inspect.signature(
-                    builtin_model["func"]
-                ).parameters.items() if v.default is inspect.Parameter.empty
-            )
-            assert builtin_model["params_required"].union(
-                {"aoi"}
-            ) == params_required_expected, model
+        params_required_expected = set(
+            k for k, v in inspect.signature(
+                builtin_model["func"]
+            ).parameters.items() if v.default is inspect.Parameter.empty
+        )
+        assert builtin_model["params_required"].union(
+            {"aoi"}
+        ) == params_required_expected, model
 
         params_optional_expected = set(
             k for k, v in inspect.signature(
@@ -266,7 +253,15 @@ def test_iam_interp():
 ])
 def test_sapm(sapm_module_params, aoi, expected):
 
-    out = _iam.sapm(aoi, sapm_module_params)
+    out = _iam.sapm(
+        aoi,
+        sapm_module_params["B0"],
+        sapm_module_params["B1"],
+        sapm_module_params["B2"],
+        sapm_module_params["B3"],
+        sapm_module_params["B4"],
+        sapm_module_params["B5"],
+    )
 
     if isinstance(aoi, pd.Series):
         assert_series_equal(out, expected, check_less_precise=4)
@@ -276,13 +271,38 @@ def test_sapm(sapm_module_params, aoi, expected):
 
 def test_sapm_limits():
     module_parameters = {'B0': 5, 'B1': 0, 'B2': 0, 'B3': 0, 'B4': 0, 'B5': 0}
-    assert _iam.sapm(1, module_parameters) == 5
+    assert _iam.sapm(
+        1,
+        module_parameters["B0"],
+        module_parameters["B1"],
+        module_parameters["B2"],
+        module_parameters["B3"],
+        module_parameters["B4"],
+        module_parameters["B5"],
+    ) == 5
 
     module_parameters = {'B0': 5, 'B1': 0, 'B2': 0, 'B3': 0, 'B4': 0, 'B5': 0}
-    assert _iam.sapm(1, module_parameters, upper=1) == 1
+    assert _iam.sapm(
+        1,
+        module_parameters["B0"],
+        module_parameters["B1"],
+        module_parameters["B2"],
+        module_parameters["B3"],
+        module_parameters["B4"],
+        module_parameters["B5"],
+        upper=1,
+    ) == 1
 
     module_parameters = {'B0': -5, 'B1': 0, 'B2': 0, 'B3': 0, 'B4': 0, 'B5': 0}
-    assert _iam.sapm(1, module_parameters) == 0
+    assert _iam.sapm(
+        1,
+        module_parameters["B0"],
+        module_parameters["B1"],
+        module_parameters["B2"],
+        module_parameters["B3"],
+        module_parameters["B4"],
+        module_parameters["B5"],
+    ) == 0
 
 
 def test_marion_diffuse_model(mocker):

pvlib/tests/test_modelchain.py

@@ -1500,10 +1500,11 @@ def test_aoi_model_user_func(sapm_dc_snl_ac_system, location, weather, mocker):
 
 
 @pytest.mark.parametrize('aoi_model', [
+    # "schlick" omitted, cannot be distinguished from "no_loss" AOI model.
     'ashrae', 'interp', 'martin_ruiz', 'physical', 'sapm'
 ])
 def test_infer_aoi_model(location, system_no_aoi, aoi_model):
-    builtin_models = iam.get_builtin_models()[aoi_model]
+    builtin_models = iam._get_builtin_models()[aoi_model]
     params = builtin_models["params_required"].union(
         builtin_models["params_optional"]
     )

pvlib/tests/test_pvsystem.py

@@ -43,11 +43,7 @@ def test_PVSystem_get_iam(mocker, iam_model, model_params):
     system = pvsystem.PVSystem(module_parameters=model_params)
     thetas = 45
     iam = system.get_iam(thetas, iam_model=iam_model)
-    if iam_model == "sapm":
-        # sapm has exceptional interface.
-        m.assert_called_with(thetas, model_params)
-    else:
-        m.assert_called_with(thetas, **model_params)
+    m.assert_called_with(thetas, **model_params)
     assert 0 < iam < 1
 
 
@@ -102,7 +98,15 @@ def test_PVSystem_get_iam_sapm(sapm_module_params, mocker):
     mocker.spy(_iam, 'sapm')
     aoi = 0
     out = system.get_iam(aoi, 'sapm')
-    _iam.sapm.assert_called_once_with(aoi, sapm_module_params)
+    _iam.sapm.assert_called_once_with(
+        aoi,
+        sapm_module_params["B0"],
+        sapm_module_params["B1"],
+        sapm_module_params["B2"],
+        sapm_module_params["B3"],
+        sapm_module_params["B4"],
+        sapm_module_params["B5"],
+    )
     assert_allclose(out, 1.0, atol=0.01)
 
 

pyproject.toml

@@ -9,7 +9,7 @@ description = "A set of functions and classes for simulating the performance of
 authors = [
     { name = "pvlib python Developers", email = "[email protected]" },
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.9, <3.13"
 dependencies = [
     'numpy >= 1.19.3',
     'pandas >= 1.3.0',
@@ -49,9 +49,9 @@ dynamic = ["version"]
 optional = [
     'cython',
     'ephem',
-    'nrel-pysam',
-    'numba >= 0.17.0',
-    'solarfactors',
+    'nrel-pysam; python_version < "3.13"',
+    'numba >= 0.17.0; python_version < "3.13"',
+    'solarfactors; python_version < "3.12"',
     'statsmodels',
 ]
 doc = [
@@ -65,7 +65,7 @@ doc = [
     'pillow',
     'sphinx-toggleprompt == 0.5.2',
     'sphinx-favicon',
-    'solarfactors',
+    'solarfactors; python_version < "3.12"',
     'sphinx-hoverxref',
 ]
 test = [