Head & Shoulder/Inverted Head & Shoulder:
x = Cum(1);
per = 5;
back=50;
inter=100;
s11=H;s12=L;
/* H & S */
pR = PeakBars( s11, per, 1 ) == 0;
endt1= LastValue(ValueWhen( pR, x, 1 ));
medt1=LastValue(ValueWhen( pR, x, 2 ));
startt1=LastValue(ValueWhen( pR, x, 3 ));
dt1=endt1-startt1;
C1=x==endt1 OR x==medt1 OR x==startt1;
endR = LastValue(ValueWhen( pR, s11, 1 ) );
medR=LastValue(ValueWhen( pR, s11, 2 ) );
startR = LastValue( ValueWhen( pR, s11, 3 ));
Filter1=medR>endR AND medR>startR AND abs(startR-endR)<0.02*(startR+endR) AND dt1<inter AND endt1>LastValue(x)-back;
MaxGraph=10;Graph1=C;Graph1Style=64;GraphXSpace=5;
/*H&S Neck Line*/
Aper=medt1-startt1;bper=endt1-medt1;
La= LastValue(ValueWhen(x==medt1,LLV(L,Aper)));
Lb=LastValue(ValueWhen(x==-1+endt1,LLV(L,bper)));
Fa=L==La AND x>startt1 AND x<medt1;
Fb=L==Lb AND x>medt1 AND x<endt1;
endt= LastValue(ValueWhen( Fb, x ));
startt=LastValue(ValueWhen( Fa, x ));
dtS =endt-startt;endS = Lb;startS = La;
aS = (endS-startS)/dtS;bS = endS;
trendlineS = aS * ( x -endt ) + bS; 
Graph3 = IIf(Filter1 AND x>startt-5,trendlineS,-1e10);Graph3BarColor=7;
/*Inverted H & S*/
tpR = TroughBars( s12, per, 1 ) == 0;
tendt1=LastValue(ValueWhen(tpr,x,1));
tmedt1=LastValue(ValueWhen(tpr,x,2));
tstartt1=LastValue(ValueWhen(tpr,x,3));
tdt1=tendt1-tstartt1;
C2=x==tendt1 OR x==tmedt1 OR x==tstartt1;
tendR = LastValue(ValueWhen( tpR, s12, 1 ) );
tmedR=LastValue(ValueWhen( tpR, s12, 2 ) );
tstartR = LastValue( ValueWhen( tpR, s12, 3 ));
Filter2=tmedR<tendR AND tmedR<tstartR AND abs(tstartR-tendR)<0.02*(tstartR+tendR) AND tdt1<inter AND tendt1>LastValue(x)-back;
Graph1BarColor=IIf(C1 AND Filter1,7,IIf(C2 AND Filter2,10,1));
/*Inverted H&S Neck Line*/
tAper=tmedt1-tstartt1;tbper=tendt1-tmedt1;
Ha= LastValue(ValueWhen(x==tmedt1,HHV(H,tAper)));
Hb=LastValue(ValueWhen(x==-1+tendt1,HHV(H,tbper)));
tFa=H==Ha AND x>tstartt1 AND x<tmedt1;
tFb=H==Hb AND x>tmedt1 AND x<tendt1;
Rendt= LastValue(ValueWhen(tFb, x ));
Rstartt=LastValue(ValueWhen( tFa, x ));
Rdt =Rendt-Rstartt;endR = Hb;startR = Ha;
aR = (endR-startR)/Rdt;bR = endR;
trendlineR = aR * ( x -Rendt ) + bR; 
Graph4 = IIf(Filter2 AND x>Rstartt-5,trendlineR,-1e10);Graph4BarColor=10;
Filter=Filter1 OR Filter2;
NumColumns=2;/*Graph2=x==-1+tendt1;*/
Column0=Filter1;
Column1=Filter2;
Column0Format=Column1Format=1.0;
Column0Name="H&S";
Column1Name="inv H&S";


Double top & bottom:
/* 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 );