split test_sdm.py accordingly

Author: kandersolar

pvlib/tests/ivtools/sdm/__init__.py

@@ -0,0 +1,12 @@
+import pytest
+
+
+@pytest.fixture
+def cec_params_cansol_cs5p_220p():
+    return {'ivcurve': {'V_mp_ref': 46.6, 'I_mp_ref': 4.73, 'V_oc_ref': 58.3,
+                        'I_sc_ref': 5.05},
+            'specs': {'alpha_sc': 0.0025, 'beta_voc': -0.19659,
+                      'gamma_pmp': -0.43, 'cells_in_series': 96},
+            'params': {'I_L_ref': 5.056, 'I_o_ref': 1.01e-10,
+                       'R_sh_ref': 837.51, 'R_s': 1.004, 'a_ref': 2.3674,
+                       'Adjust': 2.3}}

pvlib/tests/ivtools/sdm/conftest.py

@@ -0,0 +1,102 @@
+import numpy as np
+
+import pytest
+from numpy.testing import assert_allclose
+
+from pvlib.ivtools.sdm._fit_desoto_pvsyst_sandia import (
+    _calc_theta_phi_exact,
+    _update_rsh_fixed_pt,
+    _update_io
+)
+
+
+@pytest.mark.parametrize('vmp, imp, iph, io, rs, rsh, nnsvth, expected', [
+    (2., 2., 2., 2., 2., 2., 2., np.nan),
+    (2., 2., 0., 2., 2., 2., 2., np.nan),
+    (2., 2., 2., 0., 2., 2., 2., np.nan),
+    (2., 2., 2., 2., 0., 2., 2., np.nan),
+    (2., 2., 2., 2., 2., 0., 2., np.nan),
+    (2., 2., 2., 2., 2., 2., 0., np.nan)])
+def test__update_rsh_fixed_pt_nans(vmp, imp, iph, io, rs, rsh, nnsvth,
+                                   expected):
+    outrsh = _update_rsh_fixed_pt(vmp, imp, iph, io, rs, rsh, nnsvth)
+    assert np.all(np.isnan(outrsh))
+
+
+def test__update_rsh_fixed_pt_vmp0():
+    outrsh = _update_rsh_fixed_pt(vmp=0., imp=2., iph=2., io=2., rs=2.,
+                                  rsh=2., nnsvth=2.)
+    assert_allclose(outrsh, np.array([502.]), atol=.0001)
+
+
+def test__update_rsh_fixed_pt_vector():
+    outrsh = _update_rsh_fixed_pt(rsh=np.array([-1., 3, .5, 2.]),
+                                  rs=np.array([1., -.5, 2., 2.]),
+                                  io=np.array([.2, .3, -.4, 2.]),
+                                  iph=np.array([-.1, 1, 3., 2.]),
+                                  nnsvth=np.array([4., -.2, .1, 2.]),
+                                  imp=np.array([.2, .2, -1., 2.]),
+                                  vmp=np.array([0., -1, 0., 0.]))
+    assert np.all(np.isnan(outrsh[0:3]))
+    assert_allclose(outrsh[3], np.array([502.]), atol=.0001)
+
+
+@pytest.mark.parametrize('voc, iph, io, rs, rsh, nnsvth, expected', [
+    (2., 2., 2., 2., 2., 2., 0.5911),
+    (2., 2., 2., 0., 2., 2., 0.5911),
+    (2., 2., 0., 2., 2., 2., 0.),
+    (2., 0., 2., 2., 2., 2., 1.0161e-4),
+    (0., 2., 2., 2., 2., 2., 17.9436)])
+def test__update_io(voc, iph, io, rs, rsh, nnsvth, expected):
+    outio = _update_io(voc, iph, io, rs, rsh, nnsvth)
+    assert_allclose(outio, expected, atol=.0001)
+
+
+@pytest.mark.parametrize('voc, iph, io, rs, rsh, nnsvth', [
+    (2., 2., 2., 2., 2., 0.),
+    (-1., -1., -1., -1., -1., -1.)])
+def test__update_io_nan(voc, iph, io, rs, rsh, nnsvth):
+    outio = _update_io(voc, iph, io, rs, rsh, nnsvth)
+    assert np.isnan(outio)
+
+
+@pytest.mark.parametrize('vmp, imp, iph, io, rs, rsh, nnsvth, expected', [
+    (2., 2., 2., 2., 2., 2., 2., (1.8726, 2.)),
+    (2., 0., 2., 2., 2., 2., 2., (1.8726, 3.4537)),
+    (2., 2., 0., 2., 2., 2., 2., (1.2650, 0.8526)),
+    (0., 2., 2., 2., 2., 2., 2., (1.5571, 2.))])
+def test__calc_theta_phi_exact(vmp, imp, iph, io, rs, rsh, nnsvth, expected):
+    theta, phi = _calc_theta_phi_exact(vmp, imp, iph, io, rs, rsh, nnsvth)
+    assert_allclose(theta, expected[0], atol=.0001)
+    assert_allclose(phi, expected[1], atol=.0001)
+
+
+@pytest.mark.parametrize('vmp, imp, iph, io, rs, rsh, nnsvth', [
+    (2., 2., 2., 0., 2., 2., 2.),
+    (2., 2., 2., 2., 2., 2., 0.),
+    (2., 0., 2., 2., 2., 0., 2.)])
+def test__calc_theta_phi_exact_both_nan(vmp, imp, iph, io, rs, rsh, nnsvth):
+    theta, phi = _calc_theta_phi_exact(vmp, imp, iph, io, rs, rsh, nnsvth)
+    assert np.isnan(theta)
+    assert np.isnan(phi)
+
+
+def test__calc_theta_phi_exact_one_nan():
+    theta, phi = _calc_theta_phi_exact(imp=2., iph=2., vmp=2., io=2.,
+                                       nnsvth=2., rs=0., rsh=2.)
+    assert np.isnan(theta)
+    assert_allclose(phi, 2., atol=.0001)
+
+
+def test__calc_theta_phi_exact_vector():
+    theta, phi = _calc_theta_phi_exact(imp=np.array([1., -1.]),
+                                       iph=np.array([-1., 1.]),
+                                       vmp=np.array([1., -1.]),
+                                       io=np.array([-1., 1.]),
+                                       nnsvth=np.array([1., -1.]),
+                                       rs=np.array([-1., 1.]),
+                                       rsh=np.array([1., -1.]))
+    assert np.isnan(theta[0])
+    assert np.isnan(theta[1])
+    assert np.isnan(phi[0])
+    assert_allclose(phi[1], 2.2079, atol=.0001)

pvlib/tests/ivtools/sdm/test__fit_desoto_pvsyst_sandia.py

@@ -0,0 +1,41 @@
+import numpy as np
+import pandas as pd
+
+import pytest
+
+from pvlib.ivtools import sdm
+
+from pvlib.tests.conftest import requires_pysam
+
+
+@requires_pysam
+def test_fit_cec_sam(cec_params_cansol_cs5p_220p):
+    input_data = cec_params_cansol_cs5p_220p['ivcurve']
+    specs = cec_params_cansol_cs5p_220p['specs']
+    I_L_ref, I_o_ref, R_s, R_sh_ref, a_ref, Adjust = \
+        sdm.fit_cec_sam(
+            celltype='polySi', v_mp=input_data['V_mp_ref'],
+            i_mp=input_data['I_mp_ref'], v_oc=input_data['V_oc_ref'],
+            i_sc=input_data['I_sc_ref'], alpha_sc=specs['alpha_sc'],
+            beta_voc=specs['beta_voc'],
+            gamma_pmp=specs['gamma_pmp'],
+            cells_in_series=specs['cells_in_series'])
+    expected = pd.Series(cec_params_cansol_cs5p_220p['params'])
+    modeled = pd.Series(index=expected.index, data=np.nan)
+    modeled['a_ref'] = a_ref
+    modeled['I_L_ref'] = I_L_ref
+    modeled['I_o_ref'] = I_o_ref
+    modeled['R_s'] = R_s
+    modeled['R_sh_ref'] = R_sh_ref
+    modeled['Adjust'] = Adjust
+    assert np.allclose(modeled.values, expected.values, rtol=5e-2)
+
+
+@requires_pysam
+def test_fit_cec_sam_estimation_failure(cec_params_cansol_cs5p_220p):
+    # Failing to estimate the parameters for the CEC SDM model should raise an
+    # exception.
+    with pytest.raises(RuntimeError):
+        sdm.fit_cec_sam(celltype='polySi', v_mp=0.45, i_mp=5.25, v_oc=0.55,
+                        i_sc=5.5, alpha_sc=0.00275, beta_voc=0.00275,
+                        gamma_pmp=0.0055, cells_in_series=1, temp_ref=25)

pvlib/tests/ivtools/sdm/test_cec.py

@@ -0,0 +1,70 @@
+import numpy as np
+import pandas as pd
+
+import pytest
+
+from pvlib.ivtools import sdm
+from pvlib import pvsystem
+
+from pvlib.tests.conftest import requires_statsmodels
+
+
+def test_fit_desoto():
+    result, _ = sdm.fit_desoto(v_mp=31.0, i_mp=8.71, v_oc=38.3, i_sc=9.43,
+                               alpha_sc=0.005658, beta_voc=-0.13788,
+                               cells_in_series=60)
+    result_expected = {'I_L_ref': 9.45232,
+                       'I_o_ref': 3.22460e-10,
+                       'R_s': 0.297814,
+                       'R_sh_ref': 125.798,
+                       'a_ref': 1.59128,
+                       'alpha_sc': 0.005658,
+                       'EgRef': 1.121,
+                       'dEgdT': -0.0002677,
+                       'irrad_ref': 1000,
+                       'temp_ref': 25}
+    assert np.allclose(pd.Series(result), pd.Series(result_expected),
+                       rtol=1e-4)
+
+
+def test_fit_desoto_failure():
+    with pytest.raises(RuntimeError) as exc:
+        sdm.fit_desoto(v_mp=31.0, i_mp=8.71, v_oc=38.3, i_sc=9.43,
+                       alpha_sc=0.005658, beta_voc=-0.13788,
+                       cells_in_series=10)
+    assert ('Parameter estimation failed') in str(exc.value)
+
+
+@requires_statsmodels
+def test_fit_desoto_sandia(cec_params_cansol_cs5p_220p):
+    # this test computes a set of IV curves for the input fixture, fits
+    # the De Soto model to the calculated IV curves, and compares the fitted
+    # parameters to the starting values
+    params = cec_params_cansol_cs5p_220p['params']
+    params.pop('Adjust')
+    specs = cec_params_cansol_cs5p_220p['specs']
+    effective_irradiance = np.array([400., 500., 600., 700., 800., 900.,
+                                     1000.])
+    temp_cell = np.array([15., 25., 35., 45.])
+    ee = np.tile(effective_irradiance, len(temp_cell))
+    tc = np.repeat(temp_cell, len(effective_irradiance))
+    IL, I0, Rs, Rsh, nNsVth = pvsystem.calcparams_desoto(
+        ee, tc, alpha_sc=specs['alpha_sc'], **params)
+    ivcurve_params = dict(photocurrent=IL, saturation_current=I0,
+                          resistance_series=Rs, resistance_shunt=Rsh,
+                          nNsVth=nNsVth)
+    sim_ivcurves = pvsystem.singlediode(**ivcurve_params).to_dict('series')
+    v = np.linspace(0., sim_ivcurves['v_oc'], 300)
+    i = pvsystem.i_from_v(voltage=v, **ivcurve_params)
+    sim_ivcurves.update(v=v.T, i=i.T, ee=ee, tc=tc)
+
+    result = sdm.fit_desoto_sandia(sim_ivcurves, specs)
+    modeled = pd.Series(index=params.keys(), data=np.nan)
+    modeled['a_ref'] = result['a_ref']
+    modeled['I_L_ref'] = result['I_L_ref']
+    modeled['I_o_ref'] = result['I_o_ref']
+    modeled['R_s'] = result['R_s']
+    modeled['R_sh_ref'] = result['R_sh_ref']
+    expected = pd.Series(params)
+    assert np.allclose(modeled[params.keys()].values,
+                       expected[params.keys()].values, rtol=5e-2)