How is RSI calculated by Kite? Discrepancy observed on kite website

abokade

I tried calculating RSI based on explanation https://zerodha.com/varsity/chapter/indicators-part-1/
I took the closing price of SUZLON on daily time frame from 21-12-22 to 9-01-23. The RSI value is coming out to be 50 in calculation but on kite chart its showing 52.0. I tried with multiple scripts but same discrepancy is observed.

tonystark

Could you post code that resulted in these values?

Make sure to use double precision floating points while doing the calculations.

abokade

@tonystark This is the code I wrote in C#:

public static double CalculateRsi(IEnumerable closePrices, int interval)
{

var prices = closePrices as double[] ?? closePrices.ToArray();

double sumGain = 0;
double sumLoss = 0;

for (int i = 1; i < prices.Length; i++)
{
var difference = prices[i] - prices[i - 1];
if (difference >= 0)
{
sumGain += difference;
}
else
{

sumLoss -= difference;
}


}

var averageGain = sumGain / 14;
var averageLoss = sumLoss / 14;

var relativeStrength = averageGain / averageLoss;
double rsi = 100 - (100 / (1 + relativeStrength));

return rsi;

}

tonystark

I think this tradingqna thread answers your question. To quote, Varsity is showing a simple average, I assume to simplify the example calculations, and Charts/Excel takes smoothed average.

For reference ChartIQ documentation: https://documentation.chartiq.com/tutorial-Using%20and%20Customizing%20Studies%20-%20Definitions.html#rsi