def sol_tov(rho_center):
rmin = dr
rmax = 20000.0
r = pylab.arange(rmin, rmax + dr, dr)
m = pylab.zeros_like(r)
P = pylab.zeros_like(r)
m[0] = (4.0 / 3.0) * pi * rho_center * r[0]**3
P[0] = eos(rho_center)
y = pylab.array([P[0], m[0]])
i = 0
while P[i] > 0.0 and i < len(r) - 1:
y = rk4(tov, y, r[i], dr)
P[i + 1] = y[0]
m[i + 1] = y[1]
i = i + 1
rho = pylab.array(list(map(lambda p: inv_eos(p), P)))
m, r, rho, P = m[:i], r[:i], rho[:i], P[:i] # Give restriction for region
if isentropic: # Consider the isentropic case
# We use conventional finite differencing to handle this case
drhodr = get_dfdr(rho, dr)
rprime = (r[-1] - r)[::-1] # Inward integration variable
# Specific internal energy from thermo identities
u_integrand = (-P * drhodr / (rho**2))[::-1]
# Interpolation
integrand_interpol = iterp1d(rprime, u_integrand, kind='cubic')
urhs = lambda u, rprime: integrand_interpol(rprime)
u = np.zeros_like(r)
for i in range(0, len(rprime) - 1):
u[i + 1] = rk4(urhs, u[i], rprime[i], dr) # Using RK4 to integrate
u = u[::-1] # Reverse u
else:
u = np.zeros_like(r)
return m, m[-1] / Msun, r, rho, P, u # Return the mass and radius of star
def sol_tov(rho_center):
rmin = dr
rmax = 2.e10
r = pylab.arange(rmin, rmax + dr, dr)
m = pylab.zeros_like(r)
P = pylab.zeros_like(r)
rho = pylab.zeros_like(r)
i = 0
rho[i] = rho_center
m[i] = (4.0 / 3.0) * pi * dr**3
P[i] = eos(rho_center, 0.0)
y = pylab.array([P[i], m[i]])
while P[i] > 0.0 and i < len(r) - 1:
y = rk4(tov, y, r[i], dr, rho[i])
m[i + 1] = y[1]
P[i + 1] = y[0]
rho[i + 1] = bisection(2 * rho[i], 0.1 * rho[i], 1.e-8, P[i + 1])
i = i + 1
if P[i] < 0.0:
P[i] = 0.0
rho[i] = 0.0
m, r, rho, P = m[:i], r[:i], rho[:i], P[:i] # Give restriction for region
return m, m[-1] / Msun, r, rho, P # Return the mass and radius of star