apps121025_test_liouville.app05_multiple

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 .app04_nrm_setup import kep_particle

def main():

    ### Reference condition at t=0.  For 2D.
    pos0ref = np.array([1.2317, 0, 0])
    vel0ref = np.array([-0.52318 * 0.5, 0.52318 * np.sqrt(3./4), 0])

    ### Reference condition at t=3e5.
    pos1ref, vel1ref = kep_particle(pos0ref, vel0ref)
    pos1ref = pos1ref[-1, :]
    vel1ref = vel1ref[-1, :]

    posdel = np.array([0.001, 0.001, 0])    # Dr at t=0
    veldel = np.array([0.001, 0.001, 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[-1, :]
        vel1list[:, n] = vel1[-1, :]

    plt.figure()
    plt.subplot(231)
    plt.scatter(pos0list[0, :] - pos0ref[0], pos0list[1, :] - pos0ref[1])
    plt.subplot(232)
    plt.scatter(vel0list[0, :] - vel0ref[0], vel0list[1, :] - vel0ref[1])
    plt.subplot(233)
    plt.scatter(pos0list[0, :] - pos0ref[0], vel0list[0, :] - vel0ref[0])
    plt.subplot(234)
    plt.scatter(pos1list[0, :] - pos1ref[0], pos1list[1, :] - pos1ref[1])
    drbox = mp.Rectangle([0, 0], posdel[0], posdel[1], color='r')
    plt.gca().add_patch(drbox)
    plt.subplot(235)
    plt.scatter(vel1list[0, :] - vel1ref[0], vel1list[1, :] - vel1ref[1])
    dvbox = mp.Rectangle([0, 0], veldel[0], veldel[1], color='r')
    plt.gca().add_patch(dvbox)
    plt.subplot(236)
    plt.scatter(pos1list[0, :] - pos1ref[0], vel1list[0, :] - vel1ref[0])
    dvbox = mp.Rectangle([0, 0], posdel[0], veldel[0], color='r')
    plt.gca().add_patch(dvbox)


    plt.savefig('app05_multiple.png')
    

if __name__ == "__main__":
    import time
    t0 = time.time()
    main()
    print('Time ellapsed', time.time() - t0)