[amibroker] Help - Trying to plot linear regression lines

[ozzyapeman]

I've been trying to plot linear regression lines, with no luck. Hoping
someone can point out my error.

When I am determining to enter a trade, my trading formula tests against
the slope of the linear regression line over the last 4 Closes (in
addition to other tests). For visual tracking purposes, I want to plot
these linear regression lines.

Part of my trading formula resides in a BarCount loop, and inside this
loop I successfully populate arrays, TestSignalLong and TestSignalShort.
When these arrays are true, I want to plot the linear regression lines.

Here is what I tried coding but it does not properly plot the lines. I
get weird results:



X2                  = Cum(1);                                        //
2nd X-coordinate in Cartesian line formula: Y = M*X + B
LinePeriod       = 4;                                             //
look-back period for linear regression line
X1                  = LastValue(X2) - LinePeriod;                    //
1st X-coordinate in Cartesian line formula: Y = M*X + B
Slope             = LastValue( LinRegSlope(C, LinePeriod) );       //
this is the 'M' in Cartesian line formula:  Y = M*X + B
Intercept     = LastValue( LinRegIntercept(C, LinePeriod) );   // this
is the 'B' in Cartesian line formula:  Y = M*X + B
Y2                  = Slope * X2 + Intercept;                        //
2nd Y-coordinate in Cartesian line formula: Y = M*X + B
Y1                  = Slope * X1 + Intercept;                        //
1st Y-coordinate in Cartesian line formula: Y = M*X + B


// Barcount Loop
for (i = LinePeriod; i < BarCount; i++)
{
 
//----------------------------------------------------------------------\
------------------------------------------------------------------------
// MY TRADING FORMULA GOES HERE. DURING THE FORMULA, ARRAYS ARE FILLED
FOR:
// TestSignalLong[i] AND TestSignalShort[i], for use in the Indicator
below
//----------------------------------------------------------------------\
------------------------------------------------------------------------\
-
}


if (Status("action") == 1 /* Indicator */)
{

// Plot Linear Regression Lines for each TestSignal
   if (ParamToggle("Show slope signals", "No|Yes", True))
   {
     firstVisibleBar = Status("firstVisibleBar");
     lastVisibleBar  = Status("lastVisibleBar");
     for (b = firstVisibleBar; b < BarCount AND b <= lastVisibleBar; b++)
     {
       if (TestSignalLong[b])
       {
         RegLine = LineArray( X1[b], Y1[b], X2[b], Y2[b] );
         Plot(RegLine, "RegLine", colorBrown, styleThick | styleDashed);
       }
       if (TestSignalShort[b])
       {
         RegLine = LineArray( X1[b], Y1[b], X2[b], Y2[b] );
         Plot(RegLine, "RegLine", colorTurquoise, styleThick |
styleDashed);
       }
     }
    }

  Plot(C, "Close", colorGreen, styleThick);

  }