以零为中轴的KDJ源码

RSV:=(CLOSE-LLV(LOW,9))/(HHV(HIGH,9)-LLV(LOW,9))*100-50;
 K:SMA(RSV,3,1),COLORWHITE;
 D:SMA(K,3,1),COLORYELLOW;
 J:3*K-2*D,COLORMAGENTA;