152 lines
5.7 KiB
Python
152 lines
5.7 KiB
Python
import numpy as np
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import argparse
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def gen_plum(N, seed=None, RMAX=10):
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if not seed is None: np.random.seed(seed)
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particle_list = np.zeros((N,6))
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i = 0
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while (i < N):
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X1, X2, X3 = np.random.random(3)
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R = 1/np.sqrt(X1**(-2/3) - 1)
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if (R > RMAX): continue
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Z = (1 - 2*X2)*R
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X = np.sqrt(R**2 - Z**2) * np.cos(2*np.pi*X3)
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Y = np.sqrt(R**2 - Z**2) * np.sin(2*np.pi*X3)
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Ve = np.sqrt(2)*(1.0 + R**2)**(-0.25);
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X4, X5 = 0, 0
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while 0.1*X5 >= X4**2*(1-X4**2)**3.5:
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X4, X5 = np.random.random(2)
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V = Ve*X4
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X6, X7 = np.random.random(2)
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Vz = (1 - 2*X6)*V;
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Vx = np.sqrt(V**2 - Vz**2) * np.cos(2*np.pi*X7);
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Vy = np.sqrt(V**2 - Vz**2) * np.sin(2*np.pi*X7);
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X, Y, Z = np.array([X, Y, Z])*3*np.pi/16
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Vx, Vy, Vz = np.array([Vx, Vy, Vz])/np.sqrt(3*np.pi/16)
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particle_list[i,:] = [X, Y, Z, Vx, Vy, Vz]
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i += 1
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return particle_list
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def kepler_to_cartesian(a, e, i, Omega, w, nu, G=1.0, M=1.0):
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def to_arrays(*args):
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result = []
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for arg in args: result.append(np.atleast_1d(arg))
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return result
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a, e, i, Omega, w, nu = to_arrays(a, e, i, Omega, w, nu)
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P = [np.cos(w)*np.cos(Omega) - np.sin(w)*np.cos(i)*np.sin(Omega),
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np.cos(w)*np.sin(Omega) + np.sin(w)*np.cos(i)*np.cos(Omega),
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np.sin(w)*np.sin(i)]
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Q = [-np.sin(w)*np.cos(Omega) - np.cos(w)*np.cos(i)*np.sin(Omega),
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-np.sin(w)*np.sin(Omega) + np.cos(w)*np.cos(i)*np.cos(Omega),
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np.sin(i)*np.cos(w)]
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cosnu = np.cos(nu)
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cosE = (e+cosnu)/(1+e*cosnu)
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E = np.arccos(cosE)
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E[nu > np.pi] = 2*np.pi - E[nu > np.pi]
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X = a*((np.cos(E)-e)*P + np.sqrt(1-e**2)*np.sin(E)*Q)
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V = (np.sqrt(G*M/a)/(1-e*np.cos(E)))*(-np.sin(E)*P + np.sqrt(1-e**2)*np.cos(E)*Q)
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if X.shape[1]==1:
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X=X[:,0]
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V=V[:,0]
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return X.T, V.T
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def generate_binary(a, e, i, Omega, w, nu, m1, m2):
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X, V = kepler_to_cartesian(a, e, i, Omega, w, nu, M=m1+m2)
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q = np.double(m2)/np.double(m1)
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X1 = -q/(q+1)*X
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V1 = -q/(q+1)*V
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X2 = 1/(q+1)*X
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V2 = 1/(q+1)*V
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return X1, V1, X2, V2
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def write_phi_grape_config(**kargs):
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if 'file_name' in kargs: file_name = kargs['file_name']
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else: file_name = 'phi-GRAPE.cfg'
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f = open(file_name, 'w')
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f.write('%.4E %.4E %.4E %.4E %.4E %.4E data.con\n' % (kargs['eps'], kargs['t_end'], kargs['dt_disk'], kargs['dt_contr'], kargs['dt_bh'], kargs['eta']))
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f.close()
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def write_particles(particle_list, m=None, file_name='data.con'):
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N = particle_list.shape[0]
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if m is None:
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m = np.empty(N)
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m[:] = 1/N
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f = open(file_name, 'w')
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f.write('000000\n')
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f.write('%d\n' % N)
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f.write('0.0000000000E+00\n')
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for i in range(N):
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f.write('%06d%14.6e%14.6e%14.6e%14.6e%14.6e%14.6e%14.6e\n' % (i, m[i], particle_list[i,0], particle_list[i,1], particle_list[i,2], particle_list[i,3], particle_list[i,4], particle_list[i,5]))
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f.close()
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def gen_mask(particle_list, frac):
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N = particle_list.shape[0]
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if frac==0:
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mask = np.ones(N, dtype=int)
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elif frac==1:
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mask = np.zeros(N, dtype=int)
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else:
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X = particle_list[:,:3]
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V = particle_list[:,3:]
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L = np.linalg.norm(np.cross(X, V), axis=1)
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L_sorted = L.copy()
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L_sorted.sort()
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L_cutoff = L_sorted[int(N*frac)]
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mask = np.array(L > L_cutoff, dtype=int)
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return mask
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def write_mask(mask, file_name='grapite.mask'):
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f = open(file_name, 'w')
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for i in range(len(mask)):
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f.write('%06d %d\n' % (i, mask[i]))
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f.close()
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if __name__=='__main__':
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parser = argparse.ArgumentParser(description='Process some integers.')
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parser.add_argument('N', type=str, help='number of particles (follow by k to multiply by 1024)')
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parser.add_argument('--seed', type=int, default=42, help='random seed')
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parser.add_argument('--eps', type=np.double, default=1E-4, help='Plummer softening parameter (can be even 0)')
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parser.add_argument('--t_end', type=np.double, default=4, help='end time of calculation')
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parser.add_argument('--dt_disk', type=np.double, default=1, help='interval of snapshot files output (0xxx.dat)')
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parser.add_argument('--dt_contr', type=np.double, default=.125, help='interval for the energy control output (contr.dat)')
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parser.add_argument('--dt_bh', type=np.double, default=.125, help='interval for BH output (bh.dat & bh_nb.dat)')
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parser.add_argument('--eta', type=np.double, default=.01, help='parameter for timestep determination (0.02 or 0.01)')
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parser.add_argument('--frac', type=np.double, default=0, help='fraction of collisional particles (by angular momentum)')
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parser.add_argument('--bsmbh', type=bool, default=0, help='generate a binary supermassive black hole (parameters hardcoded in the script)')
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args = parser.parse_args()
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try:
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N = int(args.N)
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except ValueError:
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if args.N[-1]=='k': N = int(args.N[:-1])*1024
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else: raise ValueError('Unable to parse N.')
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write_phi_grape_config(**vars(args))
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particle_list = gen_plum(N, seed=args.seed)
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m = np.ones(N)/N
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if args.bsmbh:
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m1, m2 = 0.075, 0.025
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a, e, i, Omega, w, nu = 0.001, 0.5, 0, 0, 0, 0
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X1, V1, X2, V2 = generate_binary(a, e, i, Omega, w, nu, m1, m2)
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m[:2] = m1, m2
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m[2:] = 1/(N-2)
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particle_list[0,:3] = X1
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particle_list[0,3:] = V1
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particle_list[1,:3] = X2
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particle_list[1,3:] = V2
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write_particles(particle_list, m=m)
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mask = gen_mask(particle_list, args.frac)
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if args.bsmbh:
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mask[:2] = 3
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write_mask(mask)
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