How To Calculate Relative Strength Index (RSI) in Lua?

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function calculateRSI(period, closingPrices)
    local gains = {}
    local losses = {}
    
    for i=2, #closingPrices do
        local priceChange = closingPrices[i] - closingPrices[i-1]
        
        if priceChange > 0 then
            table.insert(gains, priceChange)
            table.insert(losses, 0)
        else
            table.insert(losses, math.abs(priceChange))
            table.insert(gains, 0)
        end
    end
    
    local averageGain = 0
    local averageLoss = 0
    
    for i=1, period do
        averageGain = averageGain + gains[i]
        averageLoss = averageLoss + losses[i]
    end
    
    averageGain = averageGain / period
    averageLoss = averageLoss / period
    
    local RS = averageGain / averageLoss
    local RSI = 100 - (100 / (1 + RS))
    
    return RSI
end

-- Example usage
local closingPrices = {100, 105, 110, 108, 115, 112, 120, 118, 122, 125, 130, 128, 135, 132}
local period = 14

local rsi = calculateRSI(period, closingPrices)
print("RSI: " .. rsi)