Added luminosity function integration test (#741)

examples/cosmo/luminosity_function_integration_test.py

@@ -0,0 +1,97 @@
+"""
+Camels luminosity function example
+==================================
+
+Use test cosmological simulation data (from the [CAMELS simulations](
+https://www.camel-simulations.org/)) to generate SDSS photometry and
+plot the luminosity functions.
+
+Note: this is an integration test, and requires the full camels
+snapshot and subhalo catalogue. These can be downloaded from the
+tests/data/ folder using the `download_camels.sh` script (an internet
+connection is required).
+"""
+
+import matplotlib.pyplot as plt
+import numpy as np
+
+from synthesizer.conversions import lnu_to_absolute_mag
+from synthesizer.emission_models import IncidentEmission
+from synthesizer.filters import FilterCollection
+from synthesizer.grid import Grid
+from synthesizer.load_data.load_camels import load_CAMELS_IllustrisTNG
+
+
+def calc_df(x, volume, binLimits):
+    hist, dummy = np.histogram(x, bins=binLimits)
+    hist = np.float64(hist)
+    phi = (hist / volume) / (binLimits[1] - binLimits[0])
+
+    phi_sigma = (np.sqrt(hist) / volume) / (
+        binLimits[1] - binLimits[0]
+    )  # Poisson errors
+
+    return phi, phi_sigma, hist
+
+
+h = 0.6711
+grid_dir = "../../tests/test_grid"
+grid_name = "test_grid"
+grid = Grid(grid_name, grid_dir=grid_dir)
+incident = IncidentEmission(grid)
+
+filter_codes = [f"SLOAN/SDSS.{f}" for f in ["g"]]
+fc = FilterCollection(filter_codes=filter_codes, new_lam=grid.lam)
+
+gals = load_CAMELS_IllustrisTNG(
+    "../../tests/data/",
+    snap_name="CV_0_snap_086.hdf5",
+    group_name="CV_0_fof_subhalo_tab_086.hdf5",
+)
+
+# Filter by stellar mass
+mstar_mask = np.array([np.sum(g.stars.masses) > 1e9 for g in gals])
+gals = [g for g, _m in zip(gals, mstar_mask) if _m]
+
+# Calculate g-band magnitudes
+specs = np.vstack([g.stars.get_spectra(incident).lnu for g in gals])
+phot = np.vstack(
+    [g.stars.get_photo_lnu(fc)["incident"]["SLOAN/SDSS.g"] for g in gals]
+)
+mags = lnu_to_absolute_mag(phot)
+
+# Calculate g-band luminosity function
+binlims = np.linspace(-25, -16, 12)
+bins = binlims[:-1] + (binlims[1] - binlims[0]) / 2
+phi, phi_sigma, _ = calc_df(mags, (25 / h) ** 3, binlims)
+
+# Plot luminosity function
+fig, ax = plt.subplots(1, 1)
+
+ax.plot(bins, np.log10(phi), label="Current version")
+
+# Previous 'working' version LF for reference
+# Commit hash:
+# b683b81e5de1e8c6ab6938d047cab54e7c5a2fdf
+phi_previous = [
+    -np.inf,
+    -np.inf,
+    -4.63,
+    -3.63,
+    -3.23,
+    -2.66,
+    -2.59,
+    -2.85,
+    -2.73,
+    -2.89,
+    -3.33,
+]
+
+ax.plot(bins, phi_previous, label="Previous version", ls="dashed")
+
+ax.legend()
+ax.set_xlabel("$m_{g}^{AB}$")
+ax.set_ylabel(r"$\phi \,/\, \mathrm{Mpc^{-3} \; dex^{-1}}$")
+
+plt.show()
+# plt.savefig('test_lf.png'); plt.close()

examples/cosmo/plot_parametric_young_stars.py

@@ -35,7 +35,7 @@
     model = IncidentEmission(grid)
 
     # Select a single galaxy
-    gal = gals[1]
+    gal = gals[2]
 
     # Age limit at which we replace star particles
     age_lim = 500 * Myr

tests/data/create_camels_small_snap.py

@@ -2,10 +2,10 @@
 import numpy as np
 
 _dir = "."
-snap_name = "LH_1_snap_031.hdf5"
-group_name = "LH_1_fof_subhalo_tab_031.hdf5"
+snap_name = "CV_0_snap_086.hdf5"
+group_name = "CV_0_fof_subhalo_tab_086.hdf5"
 N = 10  # number of galaxies to extract
-ignore_N = 1  # number of galaxies to ignore
+ignore_N = 10  # number of galaxies to ignore
 
 with h5py.File(f"{_dir}/{snap_name}", "r") as hf:
     form_time = hf["PartType4/GFM_StellarFormationTime"][:]

tests/data/download_camels.sh

@@ -1,11 +1,11 @@
 #!/bin/bash
 dir=./
 # $1
-snap=031
+snap=086
 # $2
-lh=1
+cv=0
 # $3
 
-wget "https://users.flatironinstitute.org/~camels/Sims/IllustrisTNG/LH/LH_${lh}/snap_$snap.hdf5" --output-document "${dir}/LH_${lh}_snap_${snap}.hdf5"
+wget "https://users.flatironinstitute.org/~camels/Sims/IllustrisTNG/CV/CV_${cv}/snapshot_$snap.hdf5" --output-document "${dir}/CV_${cv}_snap_${snap}.hdf5"
 
-wget "https://users.flatironinstitute.org/~camels/FOF_Subfind/IllustrisTNG/LH/LH_${lh}/fof_subhalo_tab_$snap.hdf5" --output-document "$dir/LH_${lh}_fof_subhalo_tab_$snap.hdf5"
+wget "https://users.flatironinstitute.org/~camels/FOF_Subfind/IllustrisTNG/CV/CV_${cv}/groups_$snap.hdf5" --output-document "$dir/CV_${cv}_fof_subhalo_tab_$snap.hdf5"