### Simplify symbolic product

As per the title, I want to simplify this product somehow.

```
var('i,r')
exp = product(1-2**(-i), i, 1, r)
```

This can be also expressed as

```
q_pochhammer(r, 2, 2)
```

However, the latest expression does not accept the symbolic variable `r`

, but only a real integer.

The main problem is that the actual computation (f.e. `exp.unhold().subs({r: 12345})`

takes a huge amount of time. Is there any way to simplify this product in sage or accelerate this computation somehow? I've already tried all the simplify/expand methods, but also the `combsimp`

method of `sympy`

.

As a side question, is there any way to use the `q_pochhammer`

function symbolically? Maybe I can use the hypergeometric simplifications on it.