sequence_last_step¶

paddle.static.nn. sequence_last_step ( input ) [source]

Only supports LoDTensor as input. Given the input LoDTensor, it will select last time-step feature of each sequence as output.

```Case 1:
input is 1-level LoDTensor:
input.lod = [[0, 2, 5, 7]]
input.data = [[1.], [3.], [2.], [4.], [6.], [5.], [1.]]
input.shape = [7, 1]

output is a LoDTensor:
out.shape = [3, 1]
out.shape[0] == len(x.lod[-1]) == 3
out.data = [[3.], [6.], [1.]], where 3.=last(1., 3.), 6.=last(2., 4., 6.), 1.=last(5., 1.)

Case 2:
input is a 2-level LoDTensor containing 3 sequences with length info [2, 0, 3],
where 0 means empty sequence.
The first sequence contains 2 subsequence with length info [1, 2];
The last sequence contains 3 subsequence with length info [1, 0, 3].
input.lod = [[0, 2, 2, 5], [0, 1, 3, 4, 4, 7]]
input.data = [[1.], [3.], [2.], [4.], [6.], [5.], [1.]]
input.shape = [7, 1]

It will apply pooling on last lod_level [0, 1, 3, 4, 4, 7]. pad_value = 0.0
output is a LoDTensor:
out.shape= [5, 1]
out.lod = [[0, 2, 2, 5]]
out.shape[0] == len(x.lod[-1]) == 5
out.data = [[1.], [2.], [4.], [0.0], [1.]]
where 1.=last(1.), 2.=last(3., 2.), 4.=last(4.), 0.0 = pad_value, 1=last(6., 5., 1.)
```
Parameters

input (Variable) – LoDTensor with lod_level no more than 2. The data type should be float32.

Returns

LoDTensor consist of the sequence’s last step vector. The data type is float32.

Return type

Variable

Examples

```import paddle