Hello! I was looking for a clenow strategy in google and came across this code. But there is a problem with it. "Variable used without having been initialized." Can anyone fix it? I have zero knowledge in coding AFL

```
////////////////////////////////////////////
// the calculation for ranking
////////////////////////////////////////////
colD = log(Close ); // the natural log of the close
colE = LinRegSlope( colD, 90 ); // this gives the slope of the regression line
// and we've manipulated it from dollars/day to average percentage move/day
colF = ( ( exp( colE ) ) ^ 250 ) - 1 ;
// we took the natural log so now reverse that and e raised to power of colE
// lets annualize it to get percentage move per year, so ^ 250 trading days (approx/year)
// strangely and unfortunately AmiBroker doesn't have R-Squared built in
colG = ( Correlation( Cum( 1 ), colD, 90 ) ^ 2 ); // 90 day R-Squared of column D, the log(C)
AdjustedSlope = colF * colG;
// this will ultimately be a Long Only Rotational system
// slope can be negative, and EnableRotational would initiate Short trades
// so a simple little manipulation will preserve rank and eliminate negative scores
score = AdjustedSlope + 100;
PositionScore = IIf( Rotate, score, scoreNoRotate ) ;
///////////////////
```