Money flow for Amibroker (AFL)

_SECTION_BEGIN("Chaikin Money Flow");

function CMF(r1)
{
Graph0=Sum(IIf( H>L && V>0,((( C-L )-( H-C )) / ( H-L ))*V,0),r1) / Sum(V,r1);

dynamic_color = IIf( Graph0> 0, colorGreen, colorRed ); 

Plot(Graph0, "Chaikin Money Flow ("+r1+")", dynamic_color, styleHistogram | styleThick); 

}

r1=Param("Periods", 21);
CMF(r1);