//+------------------------------------------------------------------+
//|                                       TestL1TrendFilterSP500.mq5 |
//|                             Copyright 2000-2026, MetaQuotes Ltd. |
//|                                              http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2000-2026, MetaQuotes Ltd."
#property link      "https://www.mql5.com"
#property version   "1.00"
#property script_show_inputs
#include <Graphics\Graphic.mqh>
//+------------------------------------------------------------------+
//| LoadData                                                         |
//+------------------------------------------------------------------+
void LoadData(string filename,vector<double> &data,int &data_count)
  {
   data_count=0;
   ResetLastError();
   int file_handle=FileOpen(filename,FILE_READ|FILE_TXT|FILE_ANSI);
   if(file_handle!=INVALID_HANDLE)
     {
      while(!FileIsEnding(file_handle))
        {
         string str=FileReadString(file_handle);
         if(data.Size()<=(ulong)data_count)
            data.Resize(data_count+1);
         data[data_count]=StringToDouble(str);
         data_count++;
        }
      FileClose(file_handle);
     }
   else
     {
      PrintFormat("Failed to open %s file, Error code = %d",filename,GetLastError());
     }
   data.Resize(data_count);
  }
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
   long chart=0;
   string name="log SP500";
   int data_count=0;
   vector<double> data_sp500;
   LoadData("snp500.txt",data_sp500,data_count);
   vector<double> data_l1_sp500;
   data_l1_sp500.Resize(data_count);
//--- L1TrendFilterLambdaMax
   double lambda_max=data_sp500.L1TrendFilterLambdaMax();
   PrintFormat("Lambda_max=%f",lambda_max);
   double lambda=50;
//--- L1TrendFilter
   bool res=data_sp500.L1TrendFilter(data_l1_sp500,lambda,false);
   if(res)
     {
      //--- prepare arrays for chart
      double x[],y[],y2[];
      ArrayResize(x,data_count);
      ArrayResize(y,data_count);
      ArrayResize(y2,data_count);
      for(int i=0; i<data_count; i++)
        {
         x[i]=i;
         y[i]=data_sp500[i];
         y2[i]=data_l1_sp500[i];
        }
      //---
      CGraphic graphic;
      if(ObjectFind(chart,name)<0)
         graphic.Create(chart,name,0,0,0,1000,600);
      else
         graphic.Attach(chart,name);
      graphic.BackgroundMain("log SP500 L1 trend filtering");
      graphic.BackgroundMainSize(16);
      graphic.HistoryNameWidth(60);
      graphic.HistoryColor(ColorToARGB(clrGray,255));
      graphic.XAxis().AutoScale(false);
      graphic.XAxis().Min(0);
      graphic.XAxis().Max(data_count);
      graphic.XAxis().DefaultStep(100);
      graphic.CurveAdd(x,y,CURVE_LINES,"SP500").LinesWidth(1);
      graphic.CurveAdd(x,y2,CURVE_LINES,"L1 trend").LinesWidth(3);
      graphic.CurvePlotAll();
      graphic.Update();
      DebugBreak();
     }
  }
//+------------------------------------------------------------------+