我有两个函数，给出精度和召回分数，我需要做一个调和平均函数，定义在同一个库中，使用这两个分数。函数如下所示：

功能如下：def precision(ref, hyp):

"""Calculates precision.

Args:

- ref: a list of 0's and 1's extracted from a reference file

- hyp: a list of 0's and 1's extracted from a hypothesis file

Returns:

- A floating point number indicating the precision of the hypothesis

"""

(n, np, ntp) = (len(ref), 0.0, 0.0)

for i in range(n):

if bool(hyp[i]):

np += 1

if bool(ref[i]):

ntp += 1

return ntp/np

def recall(ref, hyp):

"""Calculates recall.

Args:

- ref: a list of 0's and 1's extracted from a reference file

- hyp: a list of 0's and 1's extracted from a hypothesis file

Returns:

- A floating point number indicating the recall rate of the hypothesis

"""

(n, nt, ntp) = (len(ref), 0.0, 0.0)

for i in range(n):

if bool(ref[i]):

nt += 1

if bool(hyp[i]):

ntp += 1

return ntp/nt

调和平均函数是什么样子？

我只有这个，但我知道这是不对的：

^{pr2}$