def test_fit_cosmology():
"""Test fitting cosmology on simulated data."""
# Generate some fake data.
cosmo = FlatLambdaCDM(H0=70., Om0=0.25)
z = np.random.rand(200)
mb = -19.3 + cosmo.distmod(z).value
mberr = 0.2 * np.ones_like(z)
# fit to fake data
fitted_cosmo = fitting.fit_cosmology(z, mb, mberr)
# check that fitted H0 value is same as input
assert_allclose(cosmo.H0.value, fitted_cosmo.H0.value, rtol=1e-4)
DATA_URL = ("http://cdsarc.u-strasbg.fr/viz-bin/nph-Cat/"
"fits?J%2FA%2BA%2F523%2FA7")
data_fname = os.path.join("..", "data", "sndata.fits")
plot_fname = os.path.join("..", "plots", "cosmofit.png")
results_fname = os.path.join("..", "results", "results.txt")
# download the data if we haven't already done so.
if not os.path.exists(data_fname):
print("downloading data...")
data_utils.download_file(DATA_URL, data_fname)
sne = data_utils.read_sn_data(data_fname)
# Correct mb with known correction factors.
sne["mb_corr"] = sne["mb"] - 2.3 * sne["c"] + 0.128 * sne["x1"]
print("Fitting cosmology to data...")
cosmo = fitting.fit_cosmology(sne["z"], sne["mb_corr"], sne["mb_err"])
print("Plotting results to", plot_fname)
fig = fitting.plot_sn_data(sne["z"], sne["mb_corr"], sne["mb_err"],
cosmo=cosmo)
fig.savefig(plot_fname)
print("Writing results file to", results_fname)
with open(results_fname, "w") as f:
f.write("H0,Om0\n{},{}\n".format(cosmo.H0.value, cosmo.Om0))
DATA_URL = ("http://cdsarc.u-strasbg.fr/viz-bin/nph-Cat/"
"fits?J%2FA%2BA%2F523%2FA7")
data_fname = os.path.join("..", "data", "sndata.fits")
plot_fname = os.path.join("..", "plots", "cosmofit.png")
results_fname = os.path.join("..", "results", "results.txt")
# download the data if we haven't already done so.
if not os.path.exists(data_fname):
print("downloading data...")
data_utils.download_file(DATA_URL, data_fname)
sne = data_utils.read_sn_data(data_fname)
# Correct mb with known correction factors.
sne["mb_corr"] = sne["mb"] - 2.3 * sne["c"] + 0.128 * sne["x1"]
print("Fitting cosmology to data...")
cosmo = fitting.fit_cosmology(sne["z"], sne["mb_corr"], sne["mb_err"])
print("Plotting results to", plot_fname)
fig = fitting.plot_sn_data(sne["z"],
sne["mb_corr"],
sne["mb_err"],
cosmo=cosmo)
fig.savefig(plot_fname)
print("Writing results file to", results_fname)
with open(results_fname, "w") as f:
f.write("H0,Om0\n{},{}\n".format(cosmo.H0.value, cosmo.Om0))
