In Pandas there is get_dummies
method that one-hot encodes categorical variable. Now I want to do label smoothing as described in section 7.5.1 of Deep Learning book:
Label smoothing regularizes a model based on a softmax with k output values by replacing the hard 0 and 1 classification targets with targets of
eps / k
and1 - (k - 1) / k * eps
, respectively.
What would be the most efficient and/or elegant way to do label smothing in Pandas dataframe?
First, lets use much simpler equation ( ϵ
denotes how much probability mass you move from "true label" and distribute to all remaining ones).
1 -> 1 - ϵ
0 -> ϵ / (k-1)
You can simply use nice mathematical property of the above, since all you have to do is
x -> x * (1 - ϵ) + (1-x) * ϵ / (k-1)
thus if your dummy columns are a, b, c, d
just do
indices = ['a', 'b', 'c', 'd']
eps = 0.1
df[indices] = df[indices] * (1 - eps) + (1-df[indices]) * eps / (len(indices) - 1)
which for
>>> df
a b c d
0 1 0 0 0
1 0 1 0 0
2 0 0 0 1
3 1 0 0 0
4 0 1 0 0
5 0 0 1 0
returns
a b c d
0 0.900000 0.033333 0.033333 0.033333
1 0.033333 0.900000 0.033333 0.033333
2 0.033333 0.033333 0.033333 0.900000
3 0.900000 0.033333 0.033333 0.033333
4 0.033333 0.900000 0.033333 0.033333
5 0.033333 0.033333 0.900000 0.033333
as expected.
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