def test_distribution(normalization, with_errors, units): t, y, dy, fmax = null_data(units=units) if not with_errors: dy = None ls = LombScargle(t, y, dy, normalization=normalization) freq, power = ls.autopower(maximum_frequency=fmax) z = np.linspace(0, power.max(), 1000) # Test that pdf and cdf are consistent dz = z[1] - z[0] z_mid = z[:-1] + 0.5 * dz pdf = ls.distribution(z_mid) cdf = ls.distribution(z, cumulative=True) if isinstance(dz, u.Quantity): dz = dz.value assert_allclose(pdf, np.diff(cdf) / dz, rtol=1E-5, atol=1E-8) # psd normalization without specified errors produces bad results if not (normalization == 'psd' and not with_errors): # Test that observed power is distributed according to the theoretical pdf hist, bins = np.histogram(power, 30, density=True) midpoints = 0.5 * (bins[1:] + bins[:-1]) pdf = ls.distribution(midpoints) assert_allclose(hist, pdf, rtol=0.05, atol=0.05 * pdf[0])
def test_false_alarm_equivalence(method, normalization, use_errs): # Note: the PSD normalization is not equivalent to the others, in that it # depends on the absolute errors rather than relative errors. Because the # scaling contributes to the distribution, it cannot be converted directly # from any of the three normalized versions. if not HAS_SCIPY and method in ['baluev', 'davies']: pytest.skip("SciPy required") kwds = METHOD_KWDS.get(method, None) t, y, dy = make_data() if not use_errs: dy = None fmax = 5 ls = LombScargle(t, y, dy, normalization=normalization) freq, power = ls.autopower(maximum_frequency=fmax) Z = np.linspace(power.min(), power.max(), 30) fap = ls.false_alarm_probability(Z, maximum_frequency=fmax, method=method, method_kwds=kwds) # Compute the equivalent Z values in the standard normalization # and check that the FAP is consistent Z_std = convert_normalization(Z, len(t), from_normalization=normalization, to_normalization='standard', chi2_ref=compute_chi2_ref(y, dy)) ls = LombScargle(t, y, dy, normalization='standard') fap_std = ls.false_alarm_probability(Z_std, maximum_frequency=fmax, method=method, method_kwds=kwds) assert_allclose(fap, fap_std, rtol=0.1)
def test_false_alarm_equivalence(method, normalization, use_errs, units): # Note: the PSD normalization is not equivalent to the others, in that it # depends on the absolute errors rather than relative errors. Because the # scaling contributes to the distribution, it cannot be converted directly # from any of the three normalized versions. if not HAS_SCIPY and method in ['baluev', 'davies']: pytest.skip("SciPy required") kwds = METHOD_KWDS.get(method, None) t, y, dy, fmax = make_data(units=units) if not use_errs: dy = None ls = LombScargle(t, y, dy, normalization=normalization) freq, power = ls.autopower(maximum_frequency=fmax) Z = np.linspace(power.min(), power.max(), 30) fap = ls.false_alarm_probability(Z, maximum_frequency=fmax, method=method, method_kwds=kwds) # Compute the equivalent Z values in the standard normalization # and check that the FAP is consistent Z_std = convert_normalization(Z, len(t), from_normalization=normalization, to_normalization='standard', chi2_ref=compute_chi2_ref(y, dy)) ls = LombScargle(t, y, dy, normalization='standard') fap_std = ls.false_alarm_probability(Z_std, maximum_frequency=fmax, method=method, method_kwds=kwds) assert_allclose(fap, fap_std, rtol=0.1)
def test_autopower(data): t, y, dy = data ls = LombScargle(t, y, dy) kwargs = dict(samples_per_peak=6, nyquist_factor=2, minimum_frequency=2, maximum_frequency=None) freq1 = ls.autofrequency(**kwargs) power1 = ls.power(freq1) freq2, power2 = ls.autopower(**kwargs) assert_allclose(freq1, freq2) assert_allclose(power1, power2)
def test_false_alarm_smoketest(method, normalization): if not HAS_SCIPY and method in ['baluev', 'davies']: pytest.skip("SciPy required") kwds = METHOD_KWDS.get(method, None) t, y, dy = make_data() fmax = 5 ls = LombScargle(t, y, dy, normalization=normalization) freq, power = ls.autopower(maximum_frequency=fmax) Z = np.linspace(power.min(), power.max(), 30) fap = ls.false_alarm_probability(Z, maximum_frequency=fmax, method=method, method_kwds=kwds) assert len(fap) == len(Z) if method != 'davies': assert np.all(fap <= 1) assert np.all(fap[:-1] >= fap[1:]) # monotonically decreasing
def test_false_alarm_smoketest(method, normalization, units): if not HAS_SCIPY and method in ['baluev', 'davies']: pytest.skip("SciPy required") kwds = METHOD_KWDS.get(method, None) t, y, dy, fmax = make_data(units=units) ls = LombScargle(t, y, dy, normalization=normalization) freq, power = ls.autopower(maximum_frequency=fmax) Z = np.linspace(power.min(), power.max(), 30) fap = ls.false_alarm_probability(Z, maximum_frequency=fmax, method=method, method_kwds=kwds) assert len(fap) == len(Z) if method != 'davies': assert np.all(fap <= 1) assert np.all(fap[:-1] >= fap[1:]) # monotonically decreasing
def test_distribution(null_data, normalization, with_errors, fmax=40): t, y, dy = null_data if not with_errors: dy = None N = len(t) ls = LombScargle(t, y, dy, normalization=normalization) freq, power = ls.autopower(maximum_frequency=fmax) z = np.linspace(0, power.max(), 1000) # Test that pdf and cdf are consistent dz = z[1] - z[0] z_mid = z[:-1] + 0.5 * dz pdf = ls.distribution(z_mid) cdf = ls.distribution(z, cumulative=True) assert_allclose(pdf, np.diff(cdf) / dz, rtol=1E-5, atol=1E-8) # psd normalization without specified errors produces bad results if not (normalization == 'psd' and not with_errors): # Test that observed power is distributed according to the theoretical pdf hist, bins = np.histogram(power, 30, normed=True) midpoints = 0.5 * (bins[1:] + bins[:-1]) pdf = ls.distribution(midpoints) assert_allclose(hist, pdf, rtol=0.05, atol=0.05 * pdf[0])
def test_absolute_times(data, timedelta): # Make sure that we handle absolute times correctly. We also check that # TimeDelta works properly when timedelta is True. # The example data uses relative times t, y, dy = data # FIXME: There seems to be a numerical stability issue in that if we run # the algorithm with the same values but offset in time, the transit_time # is not offset by a fixed amount. To avoid this issue in this test, we # make sure the first time is also the smallest so that internally the # values of the relative time should be the same. t[0] = 0. # Add units t = t * u.day y = y * u.mag dy = dy * u.mag # We now construct a set of absolute times but keeping the rest the same start = Time('2019-05-04T12:34:56') trel = TimeDelta(t) if timedelta else t t = trel + start # and we set up two instances of LombScargle, one with absolute and one # with relative times. ls1 = LombScargle(t, y, dy) ls2 = LombScargle(trel, y, dy) kwargs = dict(samples_per_peak=6, nyquist_factor=2, minimum_frequency=2 / u.day, maximum_frequency=None) freq1 = ls1.autofrequency(**kwargs) freq2 = ls2.autofrequency(**kwargs) assert_quantity_allclose(freq1, freq2) power1 = ls1.power(freq1) power2 = ls2.power(freq2) assert_quantity_allclose(power1, power2) freq1, power1 = ls1.autopower(**kwargs) freq2, power2 = ls2.autopower(**kwargs) assert_quantity_allclose(freq1, freq2) assert_quantity_allclose(power1, power2) model1 = ls1.model(t, 2 / u.day) model2 = ls2.model(trel, 2 / u.day) assert_quantity_allclose(model1, model2) # Check model validation with pytest.raises(TypeError) as exc: ls1.model(trel, 2 / u.day) assert exc.value.args[0] == ('t was provided as a relative time but the ' 'LombScargle class was initialized with ' 'absolute times.') with pytest.raises(TypeError) as exc: ls2.model(t, 2 / u.day) assert exc.value.args[0] == ('t was provided as an absolute time but the ' 'LombScargle class was initialized with ' 'relative times.') # Check design matrix design1 = ls1.design_matrix(2 / u.day, t=t) design2 = ls2.design_matrix(2 / u.day, t=trel) assert_quantity_allclose(design1, design2) # Check design matrix validation with pytest.raises(TypeError) as exc: ls1.design_matrix(2 / u.day, t=trel) assert exc.value.args[0] == ('t was provided as a relative time but the ' 'LombScargle class was initialized with ' 'absolute times.') with pytest.raises(TypeError) as exc: ls2.design_matrix(2 / u.day, t=t) assert exc.value.args[0] == ('t was provided as an absolute time but the ' 'LombScargle class was initialized with ' 'relative times.')