wendy.py 文件源码

def potential(y,x,v,m,twopiG=1.,omega=None):
    """
    NAME:
       potential
    PURPOSE:
       compute the gravitational potential at a set of points
    INPUT:
       y - positions at which to compute the potential
       x - positions of N-body particles [N]
       v - velocities of N-body particles [N]
       m - masses of N-body particles [N]
       twopiG= (1.) value of 2 \pi G
       omega= (None) if set, frequency of external harmonic oscillator
    OUTPUT:
       potential(y)
    HISTORY:
       2017-05-12 - Written - Bovy (UofT/CCA)
    """
    if not omega is None:
        out= omega**2.*y**2./2.
    else:
        out= 0.
    return out\
        +twopiG\
        *numpy.sum(m*numpy.fabs(x-numpy.atleast_2d(y).T),axis=1)