Why aren´t these rays parallel?

[FREEN]

Hi guys!

30 min chart. Same K value - still not parallel. What did I miss? //FREEN

// highray
double highestprice = MAX(Highs[0], lookback)[0];
int highestbar = HighestBar(Highs[0], lookback);
double hprice = (Kvalue * -CurrentBar) + highestprice;
DrawRay("Highray", true, CurrentBar, hprice, highestbar, highestprice, Color.Gray, DashStyle.Dash, 1);



// lowray
double lowestprice = MIN(Lows[0], lookback)[0];
int lowestbar = LowestBar(Lows[0], lookback);
double lprice = (Kvalue * -CurrentBar) + lowestprice;
DrawRay("Lowray", true, CurrentBar, lprice, lowestbar, lowestprice, Color.Gray, DashStyle.Dash, 1);

[NinjaTrader_Dexter]

Hello FREEN,

Thank you for your post.

Gave your code a quick test using a Kvalue of 1 and lookback of 5 (complete guesses) and the rays are parallel.

You may want to use Print() to output the values of your hprice, lprice values to ensure they are as expected.

Also when using DrawRay(), having autoscale true will squish the chart down and make it hard to read, I set auto scale to false to make it easier to compare the lines.

[FREEN]

I´m using K = 0.0137 (main trend) and lookback 500 (30 min chart still). It seems the error accumulates with bars lookback. Can you replicate that error?

Edit: autoscale true/false = same error.

[NinjaTrader_Dexter]

Hello FREEN,

I tried those settings on an ES 06-11 chart and they are still drawn parallel for me. Note that if automatic scaling is on, they may shift in angle but again, they were still correct as far as I can tell.

If you are still doubting they are not parallel, you could Print() the difference between the two rays (the visible gap), the highest highs and lowest lows, and the and see if that changes unexpectedly on any bars. Printing before and after your Kvalue calculation will let you see if the math is pushing them out of line as well.

[FREEN]

Thanks Dexter!

Is there a way to refer to the "Lowray" and "Highray" draw objects as variables? " double diff = Highray - Lowray " would be conventient in your debug suggestion?!

[NinjaTrader_Dexter]

Hello FREEN,

You can keep track of objects with IDrawObject but it is a little more advanced. Unfortunately, you could not subtract two IDrawObjects to get the relevant underlying positions. You can however Print these objects to see what values were used, or do the math yourself. For example:

IDrawObject lowRay;
lowRay = DrawRay("Lowray", true, CurrentBar, lprice, lowestbar, lowestprice, Color.Gray, DashStyle.Dash, 1);
Print(lowRay.ToString());

This will output something along these lines:

Name='Ray' Time='4/3/2011 4:15:00 PM', StartBar='0' StartY='1273.90' EndTime='4/18/2011 10:45:00 PM' EndBar='1043' EndY='1295.00'

Alternatively you can just print the difference between lprice and lowestprice vs hprice and highestprice. Print("hprice - lprice = " + (hprice - lprice)); and so forth.

If the lines still appear to be not parallel to each other, please attach a screenshot of what you are seeing so we can check it out. Thank you

[FREEN]

Sorry my stupidity... "Print(hprice - lprice);" was the obvious answere. I appreciate your explanation on IDrawObjects however.


I made a test on ES 06-11 as well, but "Print(hprice - lprice)" does not print a consistent diff. I can´t even find the logic since it includes both conv/lower and div/higher values. I´ll post a screenshot, but it´s not really evident there.

Thanks, Fredrik

[FREEN]

Just in case in matters, here´s the all the code. There´s a midline drawn as well:

if (CurrentBar < lookback) // Return if not enough bars
{
return;
}


// highray
double highestprice = MAX(Highs[0], lookback)[0];
int highestbar = HighestBar(Highs[0], lookback);
double hprice = (Kvalue * -CurrentBar) + highestprice;
DrawRay("Highray", true, CurrentBar, hprice, highestbar, highestprice, Color.Gray, DashStyle.Dash, 1);



// lowray
double lowestprice = MIN(Lows[0], lookback)[0];
int lowestbar = LowestBar(Lows[0], lookback);
double lprice = (Kvalue * -CurrentBar) + lowestprice;
DrawRay("Lowray", true, CurrentBar, lprice, lowestbar, lowestprice, Color.Gray, DashStyle.Dash, 1);



// midray
double midestprice = (highestprice + (Kvalue * (highestbar - lowestbar)) + lowestprice) / 2;
double mprice = (hprice + lprice) / 2;
DrawRay("Midray", true, CurrentBar, mprice, lowestbar, midestprice, Color.LightGray, DashStyle.Dash, 1);


Print(hprice - lprice);
Print("");

[NinjaTrader_Dexter]

Hi Fredrik,

No problem, give printing all of your values a try.

Also just looked at the screenshot, I see what you are talking about now, thanks.

I'm suspect that the math of high and lows of the actual price data is causing the convergence. You also might be running into floating point number issues too. Perhaps using Round2TickSize() will help keep it in line with price data on the chart.

For more information on Round2TickSize(), please see http://www.ninjatrader.com/support/h...trument_ro.htm

If you can't get them in line, it might be a good idea to simplify the formula used for the Ray anchors until it works as expected and then go from there.

One last thing, would the Regression Channel indicator that comes with NinjaTrader perform what you need? You could add it to your indicator with a period of 500, and access it's Upper and Lower values. Please see http://www.ninjatrader.com/support/h...on_channel.htm


Please give the above a try and let me know if it's still occurring.

[FREEN]

Tnx Dexter! I´ll dig in to the info you provided. Xlnt support as always! : )

//Fredrik

[FREEN]

Pickin´up an old thread here since problem persists. I´ve simplified things as in code bellow to try understand where things go wrong. In a 30 min chart the ray plotted behaves erratically when zooming in/out or moving back/forth in time. The ray cuts at different prices at the same bar.

Why would this ray not behave as a ray from drawing tools?

lookback = 1000
Kvalue = .0077

double highestprice = MAX(Highs[0], lookback)[0];
int highestbar = HighestBar(Highs[0], lookback);
double hprice = (Kvalue * -CurrentBar) + highestprice;
DrawRay("Highray", false, CurrentBar, hprice, highestbar, highestprice, Color.Gray, DashStyle.Dash, 1);

[NinjaTrader_RyanM1]

Hi Freen,

Thanks for these details. Can you please post the complete script you're using so we can give it a run here. You have a multiseries script but the added series is not known.

[FREEN]

Script enclosed in support mail.

[koganam]

Hi guys!

30 min chart. Same K value - still not parallel. What did I miss? //FREEN

// highray
double highestprice = MAX(Highs[0], lookback)[0];
int highestbar = HighestBar(Highs[0], lookback);
double hprice = (Kvalue * -CurrentBar) + highestprice;
DrawRay("Highray", true, CurrentBar, hprice, highestbar, highestprice, Color.Gray, DashStyle.Dash, 1);



// lowray
double lowestprice = MIN(Lows[0], lookback)[0];
int lowestbar = LowestBar(Lows[0], lookback);
double lprice = (Kvalue * -CurrentBar) + lowestprice;
DrawRay("Lowray", true, CurrentBar, lprice, lowestbar, lowestprice, Color.Gray, DashStyle.Dash, 1);

I do not see why you expect them to be parallel. The only time that they will be parallel is if your highestbar is also your lowestbar, or if Kvalue == 0. Otherwise the anchor points do not form a parallelogram, so the line joining the upper corners will not be parallel to the line joining the lower corners. i.e., though the vertical distance between corresponding anchor points is the same, the horizontal distances will generally be different, so the lines will have different gradients.

[FREEN]

Thanks for your reply koganam,

Not sure I got your point. The ancorpoints derives from [y = kx + m] in wich all lines in a x/y diagram are parallel. As you say, the horizontal distances (the x value) will vary. But that won´t affect the gradient of the rays given the same k value.

As stated in my comment #11 even one line behaves erratically when looking in different zooms and time frames. That makes me think the calculations done are right, but the chart drawing behaves strangely.

Kindly, Fredrik