我有兩個函數，給出精度和召回分數，我需要做一個調和平均函數，定義在同一個庫中，使用這兩個分數。函數如下所示：

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

調和平均函數是什么樣子？

我只有這個，但我知道這是不對的：

^{pr2}$