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GalacticDynamicsExamples/06_plummer_intermediate_beta/density_profile.py
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density_profile.py
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import numpy as np
from matplotlib import pyplot as plt
import argparse
import h5py
import cycler
fontsz = 14
plt.rcParams.update({"text.usetex": True, "font.size": fontsz, "font.family": "serif"})
figsize = (7,5)
# Parse user input
parser = argparse.ArgumentParser(
description="Plot multiple density profiles against theoretical prediction"
)
parser.add_argument("files", nargs="+", help="snapshot files to be imaged")
parser.add_argument("-Rmin", type=float, default=0.04, help="Min Radius")
parser.add_argument("-Rmax", type=float, default=10.0, help="Max Radius")
parser.add_argument("-nbins", type=int, default=64, help="Number of radii to sample (bins)")
parser.add_argument("-shift", type=float, default=10.0, help="Shift applied to particles in params.yml")
parser.add_argument("--saveplot", action='store_true')
args = parser.parse_args()
fnames = args.files
# Limit number of snapshots to plot
if len(fnames) > 20:
raise ValueError(
"Too many ({:d}) files provided (cannot plot more than 20).".format(len(fnames))
)
# Set color cycle
ncolor = len(fnames)
color_cycle = plt.cm.plasma(np.linspace(0, 1,ncolor))
plt.rcParams['axes.prop_cycle'] = cycler.cycler('color', color_cycle)
rbins = np.logspace(np.log10(args.Rmin), np.log10(args.Rmax), args.nbins)
# Theoretical Density profile (change values of a and M if you used different ones to generate the IC)
M = 100
a = 1
G = 1
def plummer_analytical(r):
return (3.0*M/ (4.0 * np.pi * a ** 3)* (1.0 + r ** 2 / a ** 2) ** (-2.5))
v_a = np.sqrt(G * M * a**2 * (a**2 + a**2)**(-3. / 2.))
tdyn = 2*np.pi*a / v_a
t = np.empty(len(fnames))
mdens = np.empty((len(fnames),args.nbins))
# Calculate & Plot Density profile
fig, ax = plt.subplots(figsize=figsize)
ax.set_xlabel("$r$ [kpc]",fontsize=fontsz+4)
ax.set_ylabel(r"$\rho(r)$",fontsize=fontsz+4)
ax.loglog()
for j,fname in enumerate(fnames):
f = h5py.File(fname, "r")
pos = np.array(f["DMParticles"]["Coordinates"]) - args.shift
vel = np.array(f["DMParticles"]["Velocities"])
time = (f["Header"].attrs["Time"][0])
t[j] = time / tdyn
mass = np.array(f["DMParticles"]["Masses"])
r = np.sqrt(np.sum(pos ** 2, 1))
# Methods to compute density profile
def mass_ins(R):
return ((r < R) * mass).sum()
mass_ins_vect = np.vectorize(mass_ins)
def density(R):
return np.diff(mass_ins_vect(R)) / np.diff(R) / (4.0 * np.pi * R[1:] ** 2)
dens = density(rbins)
rs = rbins[1:]
# remove empty bins
c = dens > 0
dens = np.compress(c, dens)
rs = np.compress(c, rs)
# Plot
# ax.loglog(rsp[1:], density(rsp), "o", ms=1.7, label=r"$t=$ {:.3f} Gyr".format(time))
if j == 0:
ax.plot(rs, dens, label=r"$t={:.1f} \ t_{{c}}$".format(t[j]),color='black',lw=2)
else:
ax.plot(rs, dens, label=r"$t={:.1f} \ t_{{c}}$".format(t[j]))
#ax.set_ylabel(r"$\rho(r)$ [$M_{\odot}$ kpc$^{-3}$]",fontsize=fontsz+4)
ax.plot(rbins, plummer_analytical(rbins), c="darkturquoise",ls='--' ,lw=2.3,label="Plummer Theoretical")
ax.legend()
if args.saveplot:
fig.savefig("density.png",dpi=300,bbox_inches='tight')
else:
plt.show()
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