//+------------------------------------------------------------------+
//|                                                       linreg.mq4 |
//|                                         Copyright © 2006, ch33z3 |
//|                                   http://4xjournal.blogspot.com/ |
//+------------------------------------------------------------------+
#property  copyright "Copyright © 2006, ch33z3"
#property  link      "http://4xjournal.blogspot.com/"
//----
#property indicator_chart_window
#property indicator_buffers 1
#property indicator_color1 Blue
//----
extern int LRPeriod=13;
double ind_buffer[];
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
int init()
  {
   IndicatorBuffers(1);
   SetIndexStyle(0,DRAW_LINE,0,1);
   SetIndexBuffer(0,ind_buffer);
   return(0);
  }
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
int start()
  {
   int counted_bars = IndicatorCounted();
   if(counted_bars < 0)  return(-1);
   if(counted_bars > 0)   counted_bars--;
   int limit = Bars - counted_bars;
   if(counted_bars==0) limit-=1+LRPeriod;
     for(int i=limit; i>=0; i--) 
     {
      ind_buffer[i]=linreg(LRPeriod,i);
     }
   return(ind_buffer[0]);
  }
//+------------------------------------------------------------------+
double linreg(int p,int i)
  {
   double SumY=0;
   double Sum1=0;
   double Slope=0;
   double c;
     for(int x=0; x<=p-1;x++) 
     {
      c=Close[x+i];
      SumY+=c;
     Sum1+=x*c; 
     }
   double SumBars=p*(p-1)*0.5;
   double SumSqrBars=(p-1)*p*(2*p-1)/6;
   double Sum2=SumBars*SumY;
   double Num1=p*Sum1-Sum2;
   double Num2=SumBars*SumBars-p*SumSqrBars;
   if(Num2!=0) Slope=Num1/Num2;
   else Slope=0;
   double Intercept=(SumY-Slope*SumBars)/p;
   double linregval=Intercept+Slope*(p-1);
   return(linregval);
  }
//+------------------------------------------------------------------+