# tensorplay.functional.trace

Source: https://www.tensorplay.cn/docs/generated/tensorplay.functional.trace.html

```python
tensorplay.functional.trace(input) → Tensor
```

Returns the sum of the elements of the diagonal of the input 2-D matrix.

Example:

```
>>> x = tensorplay.arange(1., 10.).view(3, 3)
>>> x
tensor([[ 1.,  2.,  3.],
        [ 4.,  5.,  6.],
        [ 7.,  8.,  9.]])
>>> tensorplay.trace(x)
tensor(15.)
```