# Re: Math exp issue?

```Okay, I did a bit of testing it happens when the value of *Scl is 1 or more.
You get a similar result if you add or subtract, two or more numbers which are
not in the same format; Like one without decimal and the other with a decimal.```
```
Make sure all the values are in decimal format
with scl set properly. Most things should be OK.

(exp 2)
-> 1000002
(exp 9)
-> 1000009

(scl 1)
(+ 1 1.0)
-> 11
(- 1.0 1)
-> -9
(+ 1.0 1.0)
-> 20
-------- Original Message --------
On 29 Jan 2018 10:10 am, PositronPro wrote:

> I can't answer why it returns 1000001 for (exp 1).
>
> You can try (exp 1.0) it returns 2718282. This works fine till scl is 8 or
> less, anything more it simply returns T.
>
> (exp 1)
> -> 1000001
>
> (exp 1.0)
> ->2718282
>
> (scl 8)
> (exp 1.0)
> -> 2688...200 (50 digits number)
>
> (scl 9) # or any bigger value like 11
> -> T
> -------- Original Message --------
> On 29 Jan 2018 3:49 am, Henrik Sarvell < hsarv...@gmail.com> wrote:
>
>> Hi list, long time no see!
>> The definition of exp in math.l leads me to believe that we're calling this
>> C function:
>> https://www.tutorialspoint.com/c_standard_library/c_function_exp.htm
>>
>> Since we can't do floating numbers in PL and I notice that math.l uses (scl
>> 6) I would hope to get get something like 2718281 back from this call:
>> (println (exp 1)).
>> But that is not happening, instead I get 1000001.
>> Related is my current project which is converting this naive / simple neural
>> network written in Python to PL:
>> https://medium.com/technology-invention-and-more/how-to-build-a-simple-neural-network-in-9-lines-of-python-code-cc8f23647ca1
>>
>> Where I'm currently stuck on the sigmoid function which in turn is making
>> use of exp.```