# tensorplay.autograd.forward_ad.enter_dual_level

Source: https://www.tensorplay.cn/docs/generated/tensorplay.autograd.forward_ad.enter_dual_level.html

```python
tensorplay.autograd.forward_ad.enter_dual_level() → int
```

Enters a new forward grad level and returns its index.

This level can be used to make and unpack dual Tensors to compute
forward gradients.  Levels cannot nest: entering while another level is
active raises, so all forward AD computation happens inside one level.