def compare_evolutions():
'''
Compare precession averaged and orbit averaged integrations. Plot the
evolution of xi, J, S and their relative differences between the two
approaches. Since precession-averaged estimates of S require a random
sampling, this plot will look different every time this routine is executed.
Output is saved in ./spin_angles.pdf.
**Run using**
import precession.test
precession.test.compare_evolutions()
'''
fig = pylab.figure(figsize=(6, 6)) # Create figure object and axes
L, Ws, Wm, G = 0.85, 0.15, 0.3, 0.03 # Sizes
ax_Sd = fig.add_axes([0, 0, L, Ws]) # bottom-small
ax_S = fig.add_axes([0, Ws, L, Wm]) # bottom-main
ax_Jd = fig.add_axes([0, Ws + Wm + G, L, Ws]) # middle-small
ax_J = fig.add_axes([0, Ws + Ws + Wm + G, L, Wm]) # middle-main
ax_xid = fig.add_axes([0, 2 * (Ws + Wm + G), L, Ws]) # top-small
ax_xi = fig.add_axes([0, Ws + 2 * (Ws + Wm + G), L, Wm]) # top-main
q = 0.8 # Mass ratio. Must be q<=1.
chi1 = 0.6 # Primary spin. Must be chi1<=1
chi2 = 1. # Secondary spin. Must be chi2<=1
M, m1, m2, S1, S2 = precession.get_fixed(q, chi1,
chi2) # Total-mass units M=1
ri = 100. * M # Initial separation.
rf = 10. * M # Final separation.
r_vals = numpy.linspace(ri, rf, 1001) # Output requested
Ji = 2.24 # Magnitude of J: Jmin<J<Jmax as given by J_lim
xi = -0.5 # Effective spin: xi_low<xi<xi_up as given by xi_allowed
Jf_P = precession.evolve_J(xi, Ji, r_vals, q, S1, S2) # Pr.av. integration
Sf_P = [
precession.samplingS(xi, J, q, S1, S2, r)
for J, r in zip(Jf_P[0::10], r_vals[0::10])
] # Resample S (reduce output for clarity)
Sb_min, Sb_max = zip(*[
precession.Sb_limits(xi, J, q, S1, S2, r)
for J, r in zip(Jf_P, r_vals)
]) # Envelopes
S = numpy.average([precession.Sb_limits(xi, Ji, q, S1, S2,
ri)]) # Initialize S
Jf_O, xif_O, Sf_O = precession.orbit_averaged(Ji, xi, S, r_vals, q, S1,
S2) # Orb.av. integration
Pcol, Ocol, Dcol = 'blue', 'red', 'green'
Pst, Ost = 'solid', 'dashed'
ax_xi.axhline(xi, c=Pcol, ls=Pst, lw=2) # Plot xi, pr.av. (constant)
ax_xi.plot(r_vals, xif_O, c=Ocol, ls=Ost, lw=2) # Plot xi, orbit averaged
ax_xid.plot(r_vals, (xi - xif_O) / xi * 1e11, c=Dcol,
lw=2) # Plot xi deviations (rescaled)
ax_J.plot(r_vals, Jf_P, c=Pcol, ls=Pst, lw=2) # Plot J, pr.av.
ax_J.plot(r_vals, Jf_O, c=Ocol, ls=Ost, lw=2) # Plot J, orb.av
ax_Jd.plot(r_vals, (Jf_P - Jf_O) / Jf_O * 1e3, c=Dcol,
lw=2) # Plot J deviations (rescaled)
ax_S.scatter(r_vals[0::10], Sf_P, facecolor='none',
edgecolor=Pcol) # Plot S, pr.av. (resampled)
ax_S.plot(r_vals, Sb_min, c=Pcol, ls=Pst,
lw=2) # Plot S, pr.av. (envelopes)
ax_S.plot(r_vals, Sb_max, c=Pcol, ls=Pst,
lw=2) # Plot S, pr.av. (envelopes)
ax_S.plot(r_vals, Sf_O, c=Ocol, ls=Ost, lw=2) # Plot S, orb.av (evolved)
ax_Sd.plot(r_vals[0::10], (Sf_P - Sf_O[0::10]) / Sf_O[0::10], c=Dcol,
lw=2) # Plot S deviations
# Options for nice plotting
for ax in [ax_xi, ax_xid, ax_J, ax_Jd, ax_S, ax_Sd]:
ax.set_xlim(ri, rf)
ax.yaxis.set_label_coords(-0.16, 0.5)
ax.spines['left'].set_lw(1.5)
ax.spines['right'].set_lw(1.5)
for ax in [ax_xi, ax_J, ax_S]:
ax.spines['top'].set_lw(1.5)
for ax in [ax_xid, ax_Jd, ax_Sd]:
ax.axhline(0, c='black', ls='dotted')
ax.spines['bottom'].set_lw(1.5)
for ax in [ax_xid, ax_J, ax_Jd, ax_S]:
ax.set_xticklabels([])
ax_xi.set_ylim(-0.55, -0.45)
ax_J.set_ylim(0.4, 2.3)
ax_S.set_ylim(0.24, 0.41)
ax_xid.set_ylim(-0.2, 1.2)
ax_Jd.set_ylim(-3, 5.5)
ax_Sd.set_ylim(-0.7, 0.7)
ax_xid.yaxis.set_major_locator(matplotlib.ticker.MultipleLocator(0.5))
ax_Jd.yaxis.set_major_locator(matplotlib.ticker.MultipleLocator(2))
ax_S.yaxis.set_major_locator(matplotlib.ticker.MultipleLocator(0.05))
ax_Sd.yaxis.set_major_locator(matplotlib.ticker.MultipleLocator(0.5))
ax_xi.xaxis.set_ticks_position('top')
ax_xi.xaxis.set_label_position('top')
ax_Sd.set_xlabel("$r/M$")
ax_xi.set_xlabel("$r/M$")
ax_xi.set_ylabel("$\\xi$")
ax_J.set_ylabel("$J/M^2$")
ax_S.set_ylabel("$S/M^2$")
ax_xid.set_ylabel("$\\Delta\\xi/\\xi \;[10^{-11}]$")
ax_Jd.set_ylabel("$\\Delta J/J \;[10^{-3}]$")
ax_Sd.set_ylabel("$\\Delta S / S$")
fig.savefig("compare_evolutions.pdf", bbox_inches='tight') # Save pdf file
def phase_resampling():
'''
Precessional phase resampling. The magnidute of the total spin S is sampled
according to |dS/dt|^-1, which correspond to a flat distribution in t(S).
Output is saved in ./phase_resampling.pdf and data stored in
`precession.storedir'/phase_resampling_.dat
**Run using**
import precession.test
precession.test.phase_resampling()
'''
fig = pylab.figure(figsize=(6, 6)) #Create figure object and axes
ax_tS = fig.add_axes([0, 0, 0.6, 0.6]) #bottom-left
ax_td = fig.add_axes([0.65, 0, 0.3, 0.6]) #bottom-right
ax_Sd = fig.add_axes([0, 0.65, 0.6, 0.3]) #top-left
q = 0.5 # Mass ratio. Must be q<=1.
chi1 = 0.3 # Primary spin. Must be chi1<=1
chi2 = 0.9 # Secondary spin. Must be chi2<=1
M, m1, m2, S1, S2 = precession.get_fixed(q, chi1,
chi2) # Total-mass units M=1
r = 200. * M # Separation. Must be r>10M for PN to be valid
J = 3.14 # Magnitude of J: Jmin<J<Jmax as given by J_lim
xi = -0.01 # Effective spin: xi_low<xi<xi_up as given by xi_allowed
Sb_min, Sb_max = precession.Sb_limits(xi, J, q, S1, S2, r) # Limits in S
tau = precession.precession_period(xi, J, q, S1, S2,
r) # Precessional period
d = 2000 # Size of the statistical sample
precession.make_temp() # Create store directory, if necessary
filename = precession.storedir + "/phase_resampling.dat" # Output file name
if not os.path.isfile(filename): # Compute and store data if not present
out = open(filename, "w")
out.write("# q chi1 chi2 r J xi d\n") # Write header
out.write("# " +
' '.join([str(x)
for x in (q, chi1, chi2, r, J, xi, d)]) + "\n")
# S and t values for the S(t) plot
S_vals = numpy.linspace(Sb_min, Sb_max, d)
t_vals = numpy.array([
abs(
precession.t_of_S(Sb_min, S, Sb_min, Sb_max, xi, J, q, S1, S2,
r)) for S in S_vals
])
# Sample values of S from |dt/dS|. Distribution should be flat in t.
S_sample = numpy.array(
[precession.samplingS(xi, J, q, S1, S2, r) for i in range(d)])
t_sample = numpy.array([
abs(
precession.t_of_S(Sb_min, S, Sb_min, Sb_max, xi, J, q, S1, S2,
r)) for S in S_sample
])
# Continuous distributions (normalized)
S_distr = numpy.array([
2. * abs(precession.dtdS(S, xi, J, q, S1, S2, r) / tau)
for S in S_vals
])
t_distr = numpy.array([2. / tau for t in t_vals])
out.write("# S_vals t_vals S_sample t_sample S_distr t_distr\n")
for Sv, tv, Ss, ts, Sd, td in zip(S_vals, t_vals, S_sample, t_sample,
S_distr, t_distr):
out.write(' '.join([str(x)
for x in (Sv, tv, Ss, ts, Sd, td)]) + "\n")
out.close()
else: # Read
S_vals, t_vals, S_sample, t_sample, S_distr, t_distr = numpy.loadtxt(
filename, unpack=True)
# Rescale all time values by 10^-6, for nicer plotting
tau *= 1e-6
t_vals *= 1e-6
t_sample *= 1e-6
t_distr /= 1e-6
ax_tS.plot(S_vals, t_vals, c='blue', lw=2) # S(t) curve
ax_td.plot(t_distr, t_vals, lw=2., c='red') # Continous distribution P(t)
ax_Sd.plot(S_vals, S_distr, lw=2., c='red') # Continous distribution P(S)
ax_td.hist(t_sample,
bins=60,
range=(0, tau / 2.),
normed=True,
histtype='stepfilled',
color="blue",
alpha=0.4,
orientation="horizontal") # Histogram P(t)
ax_Sd.hist(S_sample,
bins=60,
range=(Sb_min, Sb_max),
normed=True,
histtype='stepfilled',
color="blue",
alpha=0.4) # Histogram P(S)
# Options for nice plotting
ax_tS.set_xlim(Sb_min, Sb_max)
ax_tS.set_ylim(0, tau / 2.)
ax_tS.set_xlabel("$S/M^2$")
ax_tS.set_ylabel("$t/(10^6 M)$")
ax_td.set_xlim(0, 0.5)
ax_td.set_ylim(0, tau / 2.)
ax_td.set_xlabel("$P(t)$")
ax_td.set_yticklabels([])
ax_Sd.set_xlim(Sb_min, Sb_max)
ax_Sd.set_ylim(0, 20)
ax_Sd.set_xticklabels([])
ax_Sd.set_ylabel("$P(S)$")
fig.savefig("phase_resampling.pdf", bbox_inches='tight') # Save pdf file