# `analysis.bridgeEvolution` module

Plot the evolution of the amount of matter in the bridge as a function of time for varying companion masses

Source code

    """Plot the evolution of the amount of matter in the bridge as
    a function of time for varying companion masses
    """

    import matplotlib.pyplot as plt
    import numpy as np

    from analysis import utils
    from analysis.segmentation import segmentEncounter

    # Masses are given relative to 100, with respect to the main mass
    masses = [20, 50, 100, 200]
    labels = ['1:0.25', '1:0.5', '1:1', '1:2', '1:4'] # main:companion

    f, ax = plt.subplots(1, 1, sharey=True)

    for j, style in zip(range(len(masses)), [':', '-.','-','--']):
        ts = np.linspace(4000, 10000, 61) # time range
        fractions = [] # fractional mass in bridge

        for t in ts:
            data = utils.loadData('{}mass'.format(masses[j]), int(t))
            masks, _, _ = segmentEncounter(data, mode='bridge')
            fractions.append(np.sum(masks[0])/len(data['r_vec']))

        ax.plot(ts, fractions, label=labels[j], c='black', linestyle=style)

    ax.legend(title='main:companion', fontsize=14)
    utils.setAxes(ax, x='Time', y='Fractional mass in bridge',
            xcoords=(.9,-0.08), ycoords=(-0.08,.6))
    utils.setSize(ax, x=(5000,10000), y=(0,0.1))
    utils.stylizePlot([ax])
    plt.show()