New metric estPower

[Manuel Oberti]

Ho
I Want' to create a custom metric for estimate power (estpower) for my interval analisys for EACH ride.
I have a problem with a custom metric....
The formula is : weight×9.8×slope(decimal)

My metric :

init {SLOPE<-0; seconds <0;}

sample {SLOPE <- (SLOPE/100)+ RECINTSECS;
seconds <- seconds + RECINTSECS;}

value { config(weight)×9,8×SLOPE;}
count { seconds ;}

SLOPE are decimal.....9% is 9/100 = 0.09

BUT this metric dont work

Can we help me ? THANKS

[Ale Martinez]

I have no idea what are you trying to do but to assign values to SLOPE using <- is a bad idea, use another name which don't conflict with sample variables.

[Ron George]

Manuel,

Just trying to help. 

I think you maybe trying to model climbing power...or?  

If yes,  the formula  "mass×9.8×slope(decimal) x ground speed" is consistent with the unit of watts = kg⋅m²⋅s⁻³   .  So you have to toss a speed in there.

Also : 

For steep grades, instead of simply "slope(decimal)", the expression after could be replaced with sine[arctan(slope)]. 

To put into perspective, at a steady 10% gradient, error % between the small angle approximation of (slope) and the actual formula above is about 0.5%. At a steep 20% grade, it is 1.9%. At a more difficult 30% grade, it is 4.2%. 

Cheers,

-Ron

www.georgeron.com