apps121025_test_liouville.app03_multipleΒΆ

Multiple particle, trying to estimate the amount of work.

500 particle tracing takes ~7.568 sec for my iMac. 1 hr will calculate 240000 particles.

I am still not very sure how much particles needed.

''' Multiple particle, trying to estimate the amount of work.

500 particle tracing takes ~7.568 sec for my iMac.
1 hr will calculate 240000 particles.

I am still not very sure how much particles needed.

'''
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as mp

from .app02_setup import kep_particle

def main():

### Reference condition at t=0.  For 2D.
pos0ref = np.array([4.5e8, 0, 0])
vel0ref = np.array([-10e3 * 0.5, 10e3 * np.sqrt(3./4), 0])

### Reference condition at t=3e5.
pos1ref, vel1ref = kep_particle(pos0ref, vel0ref)

posdel = np.array([5e6, 5e6, 0])    # Dr at t=0
veldel = np.array([10., 10., 0])      # Dv at t=0

drdv = posdel[0] * posdel[1] * veldel[0] * veldel[1]
print(drdv)

npart = 500

pos0list = np.zeros([3, npart])
pos1list = np.zeros([3, npart])

vel0list = np.zeros([3, npart])
vel1list = np.zeros([3, npart])

for n in range(npart):  ###  Test particles
### Calculate the position and velocity
### from the parameters defined above.
### Position (and velocity) should have
### the uniformly random from pos0ref \pm posdel/2.

posx = np.random.uniform(low=-posdel[0] / 2., high=posdel[0] / 2.) + pos0ref[0]
posy = np.random.uniform(low=-posdel[1] / 2., high=posdel[1] / 2.) + pos0ref[1]
velx = np.random.uniform(low=-veldel[0] / 2., high=veldel[0] / 2.) + vel0ref[0]
vely = np.random.uniform(low=-veldel[1] / 2., high=veldel[1] / 2.) + vel0ref[1]

pos = np.array([posx, posy, 0])
vel = np.array([velx, vely, 0])

pos0list[:, n] = pos
vel0list[:, n] = vel

pos1, vel1 = kep_particle(pos, vel)
pos1list[:, n] = pos1
vel1list[:, n] = vel1

plt.figure()
plt.subplot(221)
plt.scatter(pos0list[0, :] - pos0ref[0], pos0list[1, :] - pos0ref[1])
plt.subplot(222)
plt.scatter(vel0list[0, :] - vel0ref[0], vel0list[1, :] - vel0ref[1])
plt.subplot(223)
plt.scatter(pos1list[0, :] - pos1ref[0], pos1list[1, :] - pos1ref[1])
drbox = mp.Rectangle([0, 0], posdel[0], posdel[1], color='r')
plt.subplot(224)
plt.scatter(vel1list[0, :] - vel1ref[0], vel1list[1, :] - vel1ref[1])
dvbox = mp.Rectangle([0, 0], veldel[0], veldel[1], color='r')