Hi,

One can run `ExpValCost()`

and then access the produced samples using `device._samples`

.

In order to compute a gradient, qml optimizers perform 2 evaluations.

For example, in the case of 1-D parameter shift rule, we evaluate the circuit for `theta + s`

and `theta - s`

where `theta`

is a scalar parameter and `s`

is a scalar offset.

I would like to store the samples that were generated for `theta + s`

and `theta - s`

. How can I do this?

I imagine it should be something like

```
evaluate the function for theta + s
samples_1 = device._samples
evaluate the function for theta - s
samples_2 = device._samples
```

However, I donâ€™t want to compute samples again, I want to reuse samples that resulted from the gradient computation.