Re: How is math-round different from other Calc functions?

[Daniele Nicolodi <daniele@grinta.net>]

On 02/02/2022 09:34, Mattias Engdegård wrote:
> 1 feb. 2022 kl. 22.12 skrev Daniele Nicolodi <daniele@grinta.net>:
> 
>> (defmath uround (x)
>>   (* (round (remove-units x)) (extract-units x)))
> 
> Looks like you may need to do `math-simplify` after `remove-units`, since `math-round` only works if its argument is a value, not an unsimplified expression such as `(* (float 4 0) 1)`.
> 
>> but it does if I replace round() with any other function:
>>
>> (defmath uplus (x)
>>   (* (1+ (remove-units x)) (calc-eval "kg" 'raw)))
> 
> That `(1+ ...)` becomes `(math-add ... x)` and presumably `math-add` makes an effort to simplify its arguments for other reasons.
> 
> At least, this is from a cursory look at the code. Does that make sense?

Yes, that's it. Adding `usimplify()` I don't need to define a function 
that explicitly deals with the units:

(calc-eval "usimplify(round(2.234 g))")
"2 g"

Thank you.

Cheers,
Dan