​RSI​指标是什么意思？

AAA:=(MA(CLOSE,13)+MA(CLOSE,17))/2;
CCC:=(STD(CLOSE,13)+STD(CLOSE,17))/2;
BBB:=AAA+2.1*CCC;
DDD:=AAA+0.72*CCC;
ZZZ:=IF(CCC>1.88,MA(DDD,3),DDD);
平衡:ZZZ,COLORWHITE;
止赢:ZZZ*1.1,COLORYELLOW;
了结:ZZZ*1.05,COLORGRAY;
回档:ZZZ*0.95,COLORGREEN;
反弹:ZZZ*0.9,COLORBLUE;
DRAWTEXT(C>=1.09*REF(C,1),C,'涨停'),COLORYELLOW;
MA1:(MA(C,3)+MA(C,5))/2,COLORBLUE;
MA2:=(MA(C,8)+MA(C,13))/2,COLORYELLOW;
SFF:=H/REF(H,1)<1 AND REF(H,1)/REF(H,2)<1 AND L/REF(L,1)>1 AND REF(L,1)/REF(L,2)>1 ;
DRAWTEXT(SFF,L*0.95,'大鲨鱼：关注'),COLORYELLOW;
STICKLINE(平衡<REF(平衡,1) AND REF(平衡,1)<REF(平衡,2),平衡*1.002,平衡*0.998,3,0),COLORBLUE;
卖:DRAWTEXT(FILTER( H<=REF(H,1) AND C<REF(C,1) AND MA1<REF(MA1,1) AND H>平衡 AND 平衡<REF(平衡,1),4) OR
(H>了结 AND C<了结 AND C<O OR (H>平衡 AND C<平衡) AND C<O AND 平衡<REF(平衡,1)),H*1.01,'卖'),COLORGREEN;
买:DRAWTEXT(FILTER( C>REF(C,1) AND L>=REF(L,1) AND MA1>REF(MA1,1) AND L<平衡 AND 平衡>REF(平衡,1) OR
(L<回档 AND C>回档 AND C>O AND 平衡>REF(平衡,1) OR (L<平衡 AND C>平衡) AND C>O AND 平衡>REF(平衡,1)),5),L*0.99,'买'),COLORRED;
清仓:DRAWTEXT(H>止赢 AND C<止赢 AND C<O OR REF(C,1)>止赢 AND C<REF(C,1),止赢*0.99,'清仓'),COLORYELLOW;
满仓:DRAWTEXT((REF(C,1)<反弹 OR L<反弹) AND C>反弹 AND C>O OR FILTER(REF(C,1)<反弹 AND C>REF(C,3),5),L*0.99,'满仓'),COLORFF00FF;
选股:=(REF(C,1)<反弹 OR L<反弹) AND C>反弹 AND C>O;
买线:=EMA(C,2);
卖线:=EMA(SLOPE(C,21)*20+C,42);