functions.py 文件源码

def wilson(data):
    '''
    Calculate useful things like mass ratio and systemic velocity.

    Parameters
    ----------
    data : list
        Radial velocity pairs in a 2D list.

    Returns
    -------
    -slope : float
        Mass Ratio of the system. The ratio of the secondary
        component mass to the primary.

    intercept : float
        y-intercept of the line which fits data.

    stderr : float
        Standard error of the estimated gradient.

    '''
    from scipy.stats import linregress

    # Primary RVs on y.
    y = [datum[1] for datum in data if not np.isnan(datum[1]+datum[2])]

    # Secondary RVs on x.
    x = [datum[2] for datum in data if not np.isnan(datum[1]+datum[2])]

    slope, intercept, rvalue, pvalue, stderr = linregress(x,y)

    return -slope, intercept, stderr