def test_goodness_of_fit():
# Let's generate some data with y = Powerlaw(x)
gen_function = Powerlaw()
# Generate a dataset using the power law, and a
# constant 30% error
x = np.logspace(0, 2, 50)
xyl_generator = XYLike.from_function(
"sim_data", function=gen_function, x=x, yerr=0.3 * gen_function(x)
)
y = xyl_generator.y
y_err = xyl_generator.yerr
fit_function = Powerlaw()
xyl = XYLike("data", x, y, y_err)
parameters, like_values = xyl.fit(fit_function)
gof, all_results, all_like_values = xyl.goodness_of_fit()
# Compute the number of degrees of freedom
n_dof = len(xyl.x) - len(fit_function.free_parameters)
# Get the observed value for chi2
obs_chi2 = 2 * like_values["-log(likelihood)"]["data"]
theoretical_gof = scipy.stats.chi2(n_dof).sf(obs_chi2)
assert np.isclose(theoretical_gof, gof["total"], rtol=0.1)
def test_all():
response = OGIPResponse(
get_path_of_data_file("datasets/ogip_powerlaw.rsp"))
np.random.seed(1234)
# rescale the functions for the response
source_function = Blackbody(K=1e-7, kT=500.0)
background_function = Powerlaw(K=1, index=-1.5, piv=1.0e3)
spectrum_generator = DispersionSpectrumLike.from_function(
"fake",
source_function=source_function,
background_function=background_function,
response=response)
source_function.K.prior = Log_normal(mu=np.log(1e-7), sigma=1)
source_function.kT.prior = Log_normal(mu=np.log(300), sigma=2)
ps = PointSource("demo", 0, 0, spectral_shape=source_function)
model = Model(ps)
ba = BayesianAnalysis(model, DataList(spectrum_generator))
ba.set_sampler()
ba.sample(quiet=True)
ppc = compute_ppc(ba,
ba.results,
n_sims=500,
file_name="my_ppc.h5",
overwrite=True,
return_ppc=True)
ppc.fake.plot(bkg_subtract=True)
ppc.fake.plot(bkg_subtract=False)
