I am two tensors `A`

, `B`

, each of shape `n x n x m`

and I would like to get a tensor with dimensions `n x n`

where each entry is the dot product of long the third dimension, i.e. $$C_{ij}=\sum_k A_{ijk}B_{ijk}$$.

Example:

```
A=B=[[[ 0., 1., 2., 3., 4.], [ 5., 6., 7., 8., 9.]],
[[10., 11., 12., 13., 14.], [15., 16., 17., 18., 19.]]]
```

I would like to get

```
[[ 30., 255.],
[ 730., 1455.]]
```

Code:

```
a = torch.arange(20.).reshape(2, 2, 5)
b = torch.arange(20.).reshape(2, 2, 5)
```

to

```
for i in range(2):
for j in range(2):
d[i,j] = a[i,j].dot(b[i,j])
```

using a single operation