Homey can't count

Mathijs

start at 0 homey counts like this
0.1
0.2
0.30000000000004
0.4
0.5
etc

Same when I decrement.  Anybody any idea why Homey hates the number 3? 

JPe

After Increment use a card "Execute MathJs Expresion" with  round(WAARDE * 10) / 10  , will give you 1 dicimal always

0burner0

JPe said:

After Increment use a card "Execute MathJs Expresion" with  round(WAARDE * 10) / 10  , will give you 1 dicimal always

That is not realy a answer to his question.... I wonder to why  homey adds more than 1 if you ask home +1

JPe

sorry, it was not exactly an answer, but more a work around. 
the answer is probably because floating point values are used, then 2 + 1  is not always exactly 3 but maybe  0.30000000000004  (caused by rounding in calculations), but I'm not an expert on this.

GeurtDijker

You are using Better Logic,
I tested with Homeys build in Logic cards and this gives the same,  0.1 0.2 0.30000000000004 , 0.5, 0.6, 0.7, 0.7999999999..... 
looks like something in the core of Node.JS  / JavaScript!

googled it and found it is explained in:
https://stackoverflow.com/questions/588004/is-floating-point-math-broken

So, nothing Athom can do about it except rounding the presentation to give normal users a expected presentation.
But this could give other unwanted side effects in the end with complex calculations.

Mathijs

Damn.... that will be a complex fix for a simple problem.  I use this to set the volume of Sonos and it really does not like the volume set to 3.0000000004. 

The Execute MathJs Expresion accepts the formula "round(WAARDE * 10) / 10" but do I replace WAARDE with my variable? And what should be inserted in the Name field

TedTolboom

@Mathijs you can simply use the same tags in your calculation, see below example: https://forum.athom.com/discussion/comment/55876/#Comment_55876

in addition, I think the formula used in the referenced commment is better; "round(volume,2)"

The name field is the name of a Better Logic variable

Mathijs

Thanks!