simple initial conditions generator

gen-init.py

@@ -0,0 +1,74 @@
+import numpy as np
+import argparse
+
+def gen_plum(N, seed=None, RMAX=10):
+    if not seed is None: np.random.seed(seed)
+    particle_list = np.zeros((N,6))
+    i = 0
+    while (i < N):
+        X1, X2, X3 = np.random.random(3)
+        R = 1/np.sqrt(X1**(-2/3) - 1)
+        if (R > RMAX): continue
+        Z = (1 - 2*X2)*R
+        X = np.sqrt(R**2 - Z**2) * np.cos(2*np.pi*X3)
+        Y = np.sqrt(R**2 - Z**2) * np.sin(2*np.pi*X3)
+
+        Ve = np.sqrt(2)*(1.0 + R**2)**(-0.25);
+
+        X4, X5 = 0, 0
+        while 0.1*X5 >= X4**2*(1-X4**2)**3.5:
+            X4, X5 = np.random.random(2)
+
+        V = Ve*X4
+        X6, X7 = np.random.random(2)
+
+        Vz = (1 - 2*X6)*V;
+        Vx = np.sqrt(V**2 - Vz**2) * np.cos(2*np.pi*X7);
+        Vy = np.sqrt(V**2 - Vz**2) * np.sin(2*np.pi*X7);
+
+        X, Y, Z    = np.array([X,  Y,  Z])*3*np.pi/16
+        Vx, Vy, Vz = np.array([Vx, Vy, Vz])/np.sqrt(3*np.pi/16)
+
+        particle_list[i,:] = [X, Y, Z, Vx, Vy, Vz]
+        i += 1
+    return particle_list
+
+parser = argparse.ArgumentParser(description='Process some integers.')
+parser.add_argument('N',          type=str,                   help='The number of particles (follow by k to multiply by 1024)')
+parser.add_argument('--seed',     type=int,       default=42,   help='Random seed')
+parser.add_argument('--eps',      type=np.double, default=1E-4, help='Plummer softening parameter (can be even 0)')
+parser.add_argument('--t_end',    type=np.double, default=4,    help='end time of calculation')
+parser.add_argument('--dt_disk',  type=np.double, default=1,    help='interval of snapshot files output (0xxx.dat)')
+parser.add_argument('--dt_contr', type=np.double, default=.125, help='interval for the energy control output (contr.dat)')
+parser.add_argument('--dt_bh',    type=np.double, default=.125, help='interval for BH output (bh.dat & bh_nb.dat)')
+parser.add_argument('--eta',      type=np.double, default=.01,  help='parameter for timestep determination (0.02 or 0.01)')
+
+
+args = parser.parse_args()
+try:
+    N = int(args.N)
+except ValueError:
+    if args.N[-1]=='k': N = int(args.N[:-1])*1024
+    else: raise ValueError('Unable to parse N.')
+
+f = open('phi-GRAPE.cfg', 'w')
+f.write('%.4E %.4E %.4E %.4E %.4E %.4E data.con\n' % (args.eps, args.t_end, args.dt_disk, args.dt_contr, args.dt_bh, args.eta))
+f.close()
+
+
+particle_list = gen_plum(N)
+m = np.empty(N)
+m[:] = 1/N
+
+f = open('data.con', 'w')
+f.write('000000\n')
+f.write('%d\n' % N)
+f.write('0.0000000000E+00\n')
+for i in range(N):
+    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]))
+f.close()
+
+f = open('grapite.mask', 'w')
+for i in range(N):
+    f.write('%06d %d\n' % (i, 0))
+f.close()