def sim_crb_diff(std0, std1, N=10000):
    """ each element of std0 should correspond with the element of std1 """
    a = std0*np.random.randn(N, len(std0))
    b = std1*np.random.randn(N, len(std1))
    return a - b
def sim_crb_diff(std0, std1, N=10000):
    """ each element of std0 should correspond with the element of std1 """
    a = std0*np.random.randn(N, len(std0))
    b = std1*np.random.randn(N, len(std1))
    return a - b
def sim_crb_diff ( std0 , std1 , N = 10000 ) : a = std0 * np . random . randn ( N , len ( std0 ) ) b = std1 * np . random . randn ( N , len ( std1 ) ) return a - b
each element of std0 should correspond with the element of std1
each element of std0 should correspond with the element of std1