Dolphin shows the same behaviour. I added the following method to ScaledDecimal to help:
roundedByScale
| scaleFactor |
scaleFactor := 10 ** scale.
^(ScaledDecimal newFromNumber: (fraction * scaleFactor) rounded scale: scale) / scaleFactor
Translating slightly for Pharo:
roundedByScale
| scaleFactor |
scaleFactor := 10 ** scale.
^(ScaledDecimal newFromNumber: (self * scaleFactor) rounded scale: scale) / scaleFactor
You can then do:
(82 - (2 * 35.9) - (0 / 2) * (113/121) asScaledDecimal: 1) roundedByScale = 9.5s1 "true"
HTH.
John
On 1 Sep 2020, at 05:17, Esteban Maringolo <emaringolo@gmail.com> wrote:
As a follow up to this, adding a roundTo: before converting into a
ScaledDecimal does not work.
(((91 - (2 * 35.9) - (0 / 2) * (113/121)) roundTo: 0.1)
asScaledDecimal: 1) = 17.9s1
So how do you compare two ScaledDecimals that _should_ be the same?
Regards!
Esteban A. Maringolo
On Tue, Sep 1, 2020 at 1:07 AM Esteban Maringolo <emaringolo@gmail.com> wrote:
Hi,
I was doing some basic calculations based on a formula, and I wanted
to convert the result to a scaled decimal in order to avoid having
these "loose" decimals in 10th position or something similar.
So I did the following:
82 - (2 * 35.9) - (0 / 2) * (113/121) asScaledDecimal: 1 -> 9.5s1
But When I do this in a test:
(82 - (2 * 35.9) - (0 / 2) * (113/121) asScaledDecimal: 1) = 9.5s1
It fails because the comparison returns false.
I guess this is the proper behavior, but I'd expected that the
conversion from a Float to a scaled decimal would have eliminated the
extra precision from the formula.
I can do a roundTo: 0.1 before converting, but I'd like to know what
would be the proper way of dealing with this.
Thanks!
Esteban A. Maringolo