//SetBarsRequired( 200, 0 );

// Ehlers CyberCycle
// Cybernetic Analysis for Stocks and Futures
// Chapter 4, p. 33. Code on p. 38.
// Original code is at:
//http://www.traders.com/Documentation/FEEDbk_docs/Archive/052004/TradersTips/TradersTips.html#amibroker

function Fisher(array)
// Figure 1.7 on p. 7
{
  F = array;
  F = .25 * log((1+ array)/(1 - array)) + .5 * Ref(F, -1);
  return F;
};

function CyberCycle( array, alpha )
{
  smooth = ( array + 2 * Ref( array, -1 ) + 2 * Ref( array, -2 ) + Ref( array, -3 ) ) / 6;
  // init value
  Cycle = ( array[ 2 ] - 2 * array[ 1 ] + array[ 0 ] )/4;
  for( i = 6; i < BarCount; i++ )
  {
     Cycle[ i ] = ( ( 1 - 0.5 * alpha) ^ 2 ) *
                  ( smooth[ i ] - 2 * smooth[ i - 1 ] + smooth[ i - 2] ) +
                  2 * ( 1 - alpha ) * Cycle[ i - 1 ] -
                  ( ( 1 - alpha) ^ 2 ) * Cycle[ i - 2 ];
  }

  	MaxCycle = HHV(Cycle, 14);
  	MinCycle = LLV(Cycle, 14);
  	for (i = 0; i < BarCount; i++) {
		if (MaxCycle[i] != MinCycle[i]) {
			Value1[i] = (Cycle[i]-MinCycle[i])/(MaxCycle[i] - MinCycle[i]);
			Value2[i] = (4*Value1[i] + 3*Value1[i-1] + 2*Value1[i-2] + Value1[i-3])/10;
			Value2[i] = 2*(Value2[i] -.5);
		};
	}
  	return Value2;
}

// get log price
logprice = ln(Close);
OA1 = (logprice - Ref(logprice, -1))/sqrt(1);

// get change in bar and multiply it by the change in square root of time between yesterday AND today
n = 0;
totalprice[0]= 0;
for (i = BarCount-1; i>=1; i--){
	n = n + 1;
  	deltaPrice[i] = OA1[i]*(sqrt(n) - sqrt(n-1));
	totalprice[i]  = totalprice[i] + OA1[i]*(sqrt(n));
};

Cycle = CyberCycle( (H+L)/2, .07);
Plot( Cycle, "Stoc CyberCycle", colorBlue );
Plot( Ref(Cycle, -1), "Trigger", colorRed);