Double Top Detection for Amibroker (AFL)

/* Detecting double tops and bottoms*/
percdiff = 5; /* peak detection threshold */
fwdcheck = 5; /* forward validity check */
mindistance = 10;
validdiff = percdiff/10;

PK= Peak( H, percdiff, 1 ) == High;
TR= Trough( L, percdiff, 1 ) == Low;


x = Cum( 1 );
XPK1 = ValueWhen( PK, x, 1 );
XPK2 = ValueWhen( PK, x, 2 );
xTR1 = ValueWhen( Tr, x, 1 );
xTr2 = ValueWhen( Tr, x, 2 );

peakdiff = ValueWhen( PK, H, 1 )/ValueWhen( PK, H, 2 );
Troughdiff=ValueWhen( tr, L, 1 )/ValueWhen( tr, L, 2 );

doubletop = PK AND abs( peakdiff - 1 ) < validdiff AND (Xpk1 -Xpk2)>mindistance AND High > HHV( Ref( H, fwdcheck ), fwdcheck - 1 );
doubleBot=tr AND abs( troughdiff - 1 ) < validdiff AND (Xtr1 -Xtr2)>mindistance AND Low < LLV( Ref( L, fwdcheck ), fwdcheck - 1 );

Sell = doubletop;
Buy = doublebot;

WriteIf( Highest( doubletop ) == 1, "AmiBroker has detected some possible
double top patterns for " + Name() + "\nLook for green arrows on the price
chart.", "There are no double top patterns for " + Name() );

WriteIf(Highest( doublebot)==1,"AmiBroker has detected some possible double
bottom patterns for " + Name() + "\nLook for red arrows on the price
chart.", "There are no double bottom patterns for " + Name() );

Filter=Sell OR Buy ;

AddColumn( IIf( doubletop , 88, 01), "Double TOP", formatChar );
AddColumn( IIf( doublebot , 88, 01), "Double BOT", formatChar );