Mastering Fractals with Ring Buffer: A Guide for MetaTrader 5 Traders

Description

The CFractalsOnRingBuffer class is crafted for calculating the Fractals technical indicator using a ring buffer algorithm. For more details on the Fractals indicator, check out the official documentation here.

Class Declaration

class CFractalsOnRingBuffer

Including the Header File

#include <IncOnRingBuffer\CFractalsOnRingBuffer.mqh>

Make sure to place the CFractalsOnRingBuffer.mqh file in the IncOnRingBuffer folder, which should be created in MQL5\Include\. You'll find two example files in this folder that utilize the class. Additionally, the ring buffer class file should also be included here.

Class Methods Overview

//--- initialization method:
bool Init( // returns false on error, true on success
   int bars_right = 2, // bars right of the extremum
   int bars_left = 2, // bars left of the extremum
   int size_buffer = 256, // ring buffer size
   bool as_series = false // true for time series
   );

//--- calculation method based on time series or indicator buffers:
int MainOnArray( // returns number of processed elements
   const int rates_total, // array size
   const int prev_calculated, // previously processed elements
   const double& high[], // array of max values
   const double& low[] // array of min values
   );

//--- up fractal calculation based on high array elements:
double MainOnHigh( // returns up fractal value
   const int rates_total, // array size
   const int prev_calculated, // processed elements
   const int begin, // start of significant data
   const double high, // current bar max
   const int index // current bar index
   );

//--- down fractal calculation based on low array elements:
double MainOnLow( // returns down fractal value
   const int rates_total, // array size
   const int prev_calculated, // processed elements
   const int begin, // start of significant data
   const double low, // current bar min
   const int index // current bar index
   );

//--- data access methods:
int BarsRequired(); // returns bars needed to draw the indicator
string Name(); // returns indicator name
string NameUpper(); // returns up fractals name
string NameLower(); // returns down fractals name
int BarsRight(); // returns bars to the right from extremum
int BarsLeft(); // returns bars to the left from extremum
int Size(); // returns ring buffer size

You can access the calculated data from the ring buffers just like you would from a standard array. For example:

//--- class for calculating the Fractals indicator:
#include <IncOnRingBuffer\CFractalsOnRingBuffer.mqh>
CFractalsOnRingBuffer fractals;

...

//+------------------------------------------------------------------+
//| Custom indicator iteration function |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime& time[],
                const double& open[],
                const double& high[],
                const double& low[],
                const double& close[],
                const long& tick_volume[],
                const long& volume[],
                const int& spread[]) {
//--- calculation of the indicator based on price time series:
   fractals.MainOnArray(rates_total, prev_calculated, high, low);

...

//--- use the data from the ring buffers:
   for(int i=start; i<rates_total - BarsRight() && !IsStopped(); i++) {
     UpperBuffer[i] = fractals.upper[rates_total - 1 - i]; // up fractals
     LowerBuffer[i] = fractals.lower[rates_total - 1 - i]; // down fractals
   }

...

//--- return value of prev_calculated for next call:
   return(rates_total);
  }

Note: Indexing in the ring buffers follows the same logic as in the time series.

Examples

The Test_Fractals_OnArrayRB.mq5 file calculates the indicator based on the price time series, utilizing the MainOnArray() method.
The Test_Fractals_OnValueRB.mq5 file illustrates the use of the MainOnValue() method. Initially, the Fractals indicator is calculated and plotted, followed by drawing another Fractals using the indicator's ring buffer.