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## Re: Arbitrary precision integer arithmetic

 From: Colin Macdonald Subject: Re: Arbitrary precision integer arithmetic Date: Sat, 8 Sep 2018 23:42:07 -0700 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1

```On 2018-09-07 10:21 PM, Etienne Grossmann wrote:
```
```Hi again,

```
sorry, I didn't express myself clearly, and I didn't know about the sym() function, only the vpa() function.
```
Let's say I want to compute 423^567 exactly.

```
With the vpa() function, I have to specify the length of the result, as in vpa (vpa(423)^567, 1500).
```
```
The correct approach is to use the sym() function:  with the sym() function, sym('423^567') gives me the correct answer.
```
```
Sorry I'm late to this party. You're right; vpa is not appropriate here: that is generally for variable precision floating point (i.e., inexact with rounding).
```
Your example is most easily done as:

sym(423)^567

And if you need to type a large integer, use strings:

sym('12345682349871248651953253257235')^sym('123123124125')

- - - - -

```
intinf looks like it was great fun to write so far! If you're into this sort of thing, I can definitely use help with the Symbolic package---and even more so with upstream SymPy that powers it.
```