How TradingView Pine Script RMA works?

Question

I faced the problem that I wanted to implement the same indicators as in the trading view, but I can't correctly implement the RMA indicator.

If I refer to the documentation, I get the following code:

pine_rma(src, length) =>
    alpha = length
    sum = 0.0
    sum := na(sum[1]) ? sma(src, length) : (src + (alpha - 1) * nz(sum[1])) / alpha

Everything in it is clear to me, except for the when na(sum[1]) condition may occur. And do I understand correctly that nz(sum[1]) is the previous value of sum.

When I try to implement it in golang, they write the following code:

func RMA(value []float64, period int) float64 {
    var sum float64 

    for i := period - 1; i >= 0; i-- {
        sum = (sum * (float64(period) - 1) + value[i]) / float64(period)
    }

    return sum
}

And I am having strong discrepancies in the returned data.

I tried to understand what values are obtained in order from the RMA with a period of 3, when the input parameters for it are

src[0] = 0, src[1] = 0 and src[2] = 0.12

and we get that

rma[0] = 0.06, rma [1] = 0.04 and rma [2] = 0.03

and I don't understand where such numbers are taken, because I substitute src in the original formula, we get the most different numbers.

I took the benchmark data from the down array created for RSI from the FORD MTR CO DEL, 1D, Cboe BZX chart for September 2, 2020.

How TradingView Pine Script RMA works?

0 Answers