# bars since last occurence...

[leduc]

Dear All,

I am chewing my way through Ninja Script codeng and making some progress at last. I have a indicator that simply plots +1 and -1 for given conditions which works fine.

Second step is to find out how many bars ago the last occurence of +1 in the indicator was. In Metastock, this is a standard formula 'BarsSince(condition)' and I am looking for th NS equivalent.

In the attachment, the chart plots bars green when the indicator plots +1. The lowest indicator is my attempt to count # of bars between each green bar for which the coding is below. However, this not working as I expected.

Between occurence 0 and occurence -1 as plotted on the chart, there are 22 bars in between, indicator plots 19.

Between occurence -1 and occurence -2 as plotted on the chart, there are 38 bars in between, indicator plots 16.

Pretty sure this is doable but not quite sure ho to get there.

Any thoughts on this?
Thanks,
leduc



Coding of indicator
{
if (CurrentBar == 0)
Plot0.Set(0);
else
{
double dblPrevClose = Close[1];
double dblAtrVal = ATR(AtrLength)[1];
double dblTriggerUp = dblPrevClose + dblAtrVal;
double dblTriggerDown = dblPrevClose - dblAtrVal;
if (CrossAbove(Close, dblTriggerUp,1))
{

int intNumBarsBack = CountIf(delegate {return CrossAbove(Close, dblTriggerUp,1);}, 999);
Plot0.Set(intNumBarsBack);

[NinjaTrader_Ben]

Hello,

You could take this approach:

if(...condition here...)
{
//do something
myConditionBar = CurrentBar; //record the current bar when the condition was met
}

Then use CurrentBar minus the myConditionBar to get the spread, in bars, between when your condition was met and the current bar now.

Give that a try and post your code if you have issues. This link may be helpful:

http://www.ninjatrader-support.com/HelpGuideV6/CurrentBar.html

[leduc]

Hi,

I tried the BarsSinceSession and a For loop to get this to work...

It took me hours to go through this and the conclusion is that I need a method to hold a previous variable somwhere.

Current coding is attached in the screen print.

Idea is to loop over all price bars, finding occurrences of indicator values being equal to 1, corresponding with the green arrows in the chart in the attachement. This works in the sence that bars having the occurence are accurately marked.

Problem with the current coding is that the values in all variables are constantly reset which I understand since after the loop is over, the variables are initialized again.... This can be viewed in the ouput where variable b is always 0 while it should hold the value from the first loop

Basically, I need to know how I can keep variables alive outside the OnBarUpdateMethod for this to have a chance of working.

I hope by the way that someone will point out a buildin function to reference previous indicator values because this beginning to look more complex than need be.

Thanks,
leduc

[NinjaTrader_JoshP]

leduc,

Instead of declaring your variables in OnBarUpdate() please put it into the Variables region of your code above Initialize(). From there it will persist its values.

[leduc]

pfff, and off course I should have figured that one out.....7,5 hours on a plane staring at C# screen makes you not see the obvious I guess.

With that last remark, it is now working as expected!!!

While we are on the subject, I want the indicator to also plot a second line for reverse signals. I extended the coding by adding a new plot but it keeps complaining about not being able to recognize "Plot1"

This line was there
Add(new Plot(Color.FromKnownColor(KnownColor.Orange), PlotStyle.Line, "Plot0"));

This is what I added later.
Add(new Plot(Color.FromKnownColor(KnownColor.Black), PlotStyle.Line, "Plot1"));


When trying to plot a signal, I get the error below:
The name 'Plot1' does not exist within current context.

This must be simple I would say. I have added the full coding in the picture.

Thanks,
leduc

[NinjaTrader_Bertrand]

leduc, did you add your new Plot to the Properties section, too?

[leduc]

ehh, no I did not

I should pay more attention to all the hidden sections do doubt.

I have added some coding to the properties section and now it works!!

Thanks for all the help, I will post the revised coding with some explanations when I am done for later reference.

Thanks all,
leduc

[NinjaTrader_Bertrand]

You're welcome, great you got it figured out.

[leduc]

Frustrated...

mmm, not having much luck with that second plot.

I revised the coding and if I do not use the else statement, things for 1 plot are OK.

Using the second statement wipes out the first plot and the one that does show does not do what it should do...

It must be in the nested statements somewhere but I tried all kinds of combinations and I have not managed to at least plot 2 lines.

What gives? Coding is in the attachement

[NinjaTrader_JoshP]

leduc,

Unfortunately you will have to step through your code slowly and debug it. I suggest you use Print() statements throughout your code and try to track it along each step of the way and see where it breaks down.

[leduc]

Found the reason for the not plotting.

Values for both plots were set to 0 where each plot seems to need its own (unique value)..



#region Properties
[public DataSeries Plot0
{
get { return Values[0]; }
}
public DataSeries Plot1
{
get {return Values[1];} // This was Values[0];
}
#endregion

leduc,

Unfortunately you will have to step through your code slowly and debug it. I suggest you use Print() statements throughout your code and try to track it along each step of the way and see where it breaks down.

[leduc]

Solved!!

Actually, solved it entirly with much simpler code!!

Thanks all,
leduc

[leduc]

mmm, ran into something that I did not expect.

it seems that the indicator was doing fine but since a new day (session) started, the output is all screwed up, dropping the count to -700....

Can anyone explain this one?

leduc

[NinjaTrader_JoshP]

leduc,

Suggest you print the values of your indicator calculations on session break. You can use something like Bars.FirstBarOfSession to find the session breaks.

[leduc]

Dear All,

Fixed this one finaly today.... problem was with the barssincesession variable declared in the wrong spot.

Attached is new coding. The event declared under x can be replaced with alternative coding.

Regards,
leduc