chainer.functions.pad_sequenceのサンプル
import chainer.functions as F
import chainer
import numpy as np
a=chainer.Variable(np.array([[1],[2],[3]],dtype=np.float32))
b=chainer.Variable(np.array([[11],[12]],dtype=np.float32))
c=chainer.Variable(np.array([[21]],dtype=np.float32))
tpl=(a,b,c)
F.pad_sequence(tpl)
variable([[[ 1.],
[ 2.],
[ 3.]],
[[11.],
[12.],
[ 0.]],
[[21.],
[ 0.],
[ 0.]]])