I am creating a simple function in order to calculate Relative Strength Index ( RSI
). I am following the instructions from this website http://stockcharts.com/school/doku.php?st=stochastic+rsi&id=chart_school:technical_indicators:relative_strength_index_rsi
For those sample values the code works perfectly. But for any forex data from MetaTrader 4, the expected value in MetaTrader is different.
This is the simplified code I am using:
double CalculateRSISimple(std::vector<ROWDATA>& aData, int nPos, int RSIPeriod)
{
double dTotalGain = 0;
double dTotalLoss = 0;
double dRS = 0;
double dRSI = 0;
int nOffset = 0;
int nPrevOffset = 0;
for (int n = RSIPeriod-1; n >= 0; n--)
{
nOffset = nPos - n;
nPrevOffset = nOffset - 1;
double dDiff = aData[nOffset].dClose - aData[nPrevOffset].dClose;
if (dDiff > 0)
{
dTotalGain += dDiff;
}
else
{
dTotalLoss -= dDiff;
}
}
double dAveGain = dTotalGain / double(RSIPeriod);
double dAveLoss = dTotalLoss / double(RSIPeriod);
dRS = dAveGain / dAveLoss;
dRSI = 100.0 - (100.0 / (1 + dRS));
return dRSI;
}
It works perfectly with this sample data:
void TestRSI_1()
{
// TEST
std::vector<ROWDATA> vRowData;
ROWDATA rowTemp;
rowTemp.dClose = 44.338900;
vRowData.push_back(rowTemp);
rowTemp.dClose = 44.090200;
vRowData.push_back(rowTemp);
rowTemp.dClose = 44.149700;
vRowData.push_back(rowTemp);
rowTemp.dClose = 43.612400;
vRowData.push_back(rowTemp);
rowTemp.dClose = 44.327800;
vRowData.push_back(rowTemp);
rowTemp.dClose = 44.826400;
vRowData.push_back(rowTemp);
rowTemp.dClose = 45.095500;
vRowData.push_back(rowTemp);
rowTemp.dClose = 45.424500;
vRowData.push_back(rowTemp);
rowTemp.dClose = 45.843300;
vRowData.push_back(rowTemp);
rowTemp.dClose = 46.082600;
vRowData.push_back(rowTemp);
rowTemp.dClose = 45.893100;
vRowData.push_back(rowTemp);
rowTemp.dClose = 46.032800;
vRowData.push_back(rowTemp);
rowTemp.dClose = 45.614000;
vRowData.push_back(rowTemp);
rowTemp.dClose = 46.282000;
vRowData.push_back(rowTemp);
rowTemp.dClose = 46.282000;
vRowData.push_back(rowTemp);
double dRSI = CalculateRSISimple(vRowData, 14, 14);
if (fabs(dRSI - 70.5328) < 0.0001)
{
printf("... Test Passsed %f. Expected %f\n", dRSI, 70.5328);
}
else
{
printf("... Test Failed %f. Expected %f\n", dRSI, 70.5328);
}
}
But when I try to use Forex data, the result is totally different than the expected by MetaTrader 4:
void TestRSI_3()
{
// TEST
std::vector<ROWDATA> vRowData;
ROWDATA rowTemp;
rowTemp.dClose = 1.11919; // 0:00
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11932;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11879;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11847;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11867;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11845;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11836;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11817;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11826;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11823;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11842;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11859;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11874;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11876;
vRowData.push_back(rowTemp);
rowTemp.dClose = 1.11915;
vRowData.push_back(rowTemp);
double dRSI = CalculateRSISimple(vRowData, 14, 14);
double dExpected = 58.4792;
if (fabs(dRSI - dExpected) < 0.0001)
{
printf("... Test Passsed %f. Expected %f\n", dRSI, dExpected);
}
else
{
printf("... Test Failed %f. Expected %f\n", dRSI, dExpected);
}
}
This is the output:
Test Passsed 70.532789. Expected 70.532800
Test Failed 49.264706. Expected 58.479200
I am wondering if MetaTrader4 calculates RSI
in a different way?
Any ideas?