把多空主图做个金叉选股

b:(20*a+19*ref(a,1)+18*ref(a,2)+17*ref(a,3)+16*ref(a,4)+15*ref(a,5)+14*ref(a,6)
+13*ref(a,7)+12*ref(a,8)+11*ref(a,9)+10*ref(a,10)+9*ref(a,11)+8*ref(a,12)
+7*ref(a,13)+6*ref(a,14)+5*ref(a,15)+4*ref(a,16)+3*ref(a,17)+2*ref(a,18)+
ref(a,20))/210;
d:ma(b,m);
bu:=cross(high,SAR(3,1,20));
sel:=cross(SAR(3,1,20),low);

var1:=last(high<SAR(3,1,20));
var2:=last(low>sar(3,1,20));

drawflagtext(bu,high,'买入');
drawflagtext(sel,low,'卖出');

drawtext(bu,LOW,'B'),valign0,align1,coloryellow,linethick2;
drawtext(sel,HIGH,'S'),valign2,align1,colorgreen,linethick2;

STICKLINE(low>SAR(3,1,20) and isdown,high,open,0.5,1),colorred;
STICKLINE(low>SAR(3,1,20) and isdown,close,open,7.5,1),colorred;
STICKLINE(low>SAR(3,1,20) and isdown,close,low,0.5,1),colorred;

STICKLINE(high<SAR(3,1,20) and isup,high,close,0.5,1),colorcyan;
STICKLINE(high<SAR(3,1,20) and isup,close,open,7.5,1),colorcyan;
STICKLINE(high<SAR(3,1,20) and isup,open,low,0.5,1),colorcyan;

drawflagtext(high<SAR(3,1,20) and high>=ref(high,1),high,'明日突破'+forcast(sar(3,1,20),max(var1,2))+'建议关注');
drawflagtext(high<SAR(3,1,20) and high<ref(high,1),high,'持币观望');

drawflagtext(low>SAR(3,1,20) and low<=ref(low,1),low,'明日跌破'+forcast(sar(3,1,20),max(var2,2))+'注意止盈');
drawflagtext(low>SAR(3,1,20) and low>ref(low,1),low,'继续持股');