kernels.py 文件源码

def continuum_kernel(x):
    '''
    limit of continuum magic kernel as a piecewise function.
    See http://johncostella.webs.com/magic/

    Parameters
    ----------

    Returns
    -------
    '''
    x = np.float64(abs(x))
    return np.piecewise(x,[x>=1.5,(x>=0.5)&(x<1.5),(x>=0.0)&(x<0.5)],\
        [lambda x:0, lambda x:0.5*(x-1.5)**2, lambda x:0.75-x**2])