pine script - How to make a function if ADX is moving up or down

Question

I'm a very novice pinescript programmer, but trying to do this:

If ADX (10,10) changes direction then SellLong

SellLong = ChangeDirection(ADX(10,10))

Although ChangeDirection doesn't seem to be a function. Is ADX a built-in function? Can someone assist on this? thanks

Answer 1

ADX is comprised in the dmi() function.
This function returns 3 values:

• Positive Directional Movement (+DI)
• Negative Directional Movement (-DI)
• Average Directional Movement Index (ADX)

This is what you need:

//@version=4
study("My Script")

[di_pos, di_neg, adx] = dmi(10, 10)

SellLong = change(adx) > 0 ? true : false

plot(SellLong ? 1 : 0)