Passing Value to a method

[Wholesome]

Hi
I am trying to develop a custom slope indicator which identifies sequences of n up or down bars.
The else branch of the OnBarUpdate() method looks like this:
{
slowEma.Set((2.0 / (1 + Slow)) * Input[0] +
(1 - (2.0 / (1 + Slow))) * slowEma[1]);
double avr = slowEma[0];
Value.Set(avr);
Print(Value[0].ToString("0.00");
slope = Slopes(Value); // Sorry, I left ut the call
}
This prints Value to the output window, but if I call Slopes() with many
different ways to reference Value, either by passing it directly or assuming
it is global, it fails.

Slopes(), as defined in Indicator.UserDefinedMethods, looks like this:
public int Slopes(DataSeries Value)
{
int retval = 0;
if(Value[0] > Value[1] && Value[1] > Value[2]) retval = 1;
if(Value[0] < Value[1] && Value[1] < Value[2]) retval = -1;
return retval;
}
How do I pass the reference to Value? Thanks

[NinjaTrader_Bertrand]

Wholesome, not sure I follow - how does your call to the Slopes method look then in the code?

[Wholesome]

I left out the call

The call to Slopes();

int slope = Slopes(Value);

I just want to access the Value[] array with an index.

[NinjaTrader_JoshP]

You can't do that. Slope() requires two data points which means you need to call the DataSeries and not a specific value.

The Slope() method requires 3 parameters.

Slope(IDataSeries series, int startBarsAgo, int endBarsAgo)

[Wholesome]

Slopes() is a custom method

Hi Josh
Slopes() is a custom method I am writing (not to be confused with the Slope() method) My custom method appears at the start of this thread.
How do I access the Value[] DataSeries in a custom method. Is Value[] global, or do I pass it as an argument? If so, how do I reference it?
Thank you.

[NinjaTrader_JoshP]

Try printing Value[1] from in there. You need to first ensure that you have enough bars to actually access such an index value though. Please see this tip: http://www.ninjatrader-support2.com/...ead.php?t=3170

If you can't access it from in there then you will need to pass those values into the method as input parameters when you call Slopes() from OnBarUpdate().

[Wholesome]

Still mystified

Hi again
The Value[1] suggestion didn't work so I tried to pass the individual values. When the code looked like this in OnBarUpdate(), it printed the values and drew the average.

{
slowEma.Set((2.0 / (1 + Slow)) * Input[0] + (1 - (2.0 / (1 + Slow))) * slowEma[1]);
double avr = slowEma[0];
Value.Set(avr);
Print(Value[0].ToString("0.00");
}

When I modified the code to try to pass a single value, it didn't print or draw the average line.

{
slowEma.Set((2.0 / (1 + Slow)) * Input[0] + (1 - (2.0 / (1 + Slow))) * slowEma[1]);
double avr = slowEma[0];
Value.Set(avr);
double v0 = Value[0];
Print(v0.ToString("0.00");
}

Suggestions?

[NinjaTrader_JoshP]

Sorry I don't see where you are passing any value anywhere. All you did was set it to a double variable.

[Wholesome]

OK Here it is

HI Josh

{
slowEma.Set((2.0 / (1 + Slow)) * Input[0] + (1 - (2.0 / (1 + Slow))) * slowEma[1]);
double avr = slowEma[0];
Value.Set(avr);
double v0 = Value[0];
Print(v0.ToString("0.00"); // This failed, so I saw no point in including
int slope = Slopes(v0); // this.
}

[NinjaTrader_JoshP]

Failed as in how? If Value[0] holds a value then v0 will as well. Please print both to see.

[Wholesome]

Further clarification

HI Josh
I thought so too. I thought when I set V0 = Value[0] that they would contain the same value. I'm pretty sure Value[0] contained a valid number because I printed it to the output window. Then when I set double v0 = Value[0] and tried to print v0, the indicator, which had previously drawn a 50 bar SMA on the chart and printed Value[0] to the output window, no longer did so. That is how it failed.

[NinjaTrader_JoshP]

You will need to check your Control Center logs for errors then. If you can access Value[0] you for sure can set it to a variable.

[Wholesome]

Found the bug

Hi Josh
Here's the Print() statement:

Print(v0.ToString("0.00");

The addition of the second right paren makes it right. I've made that mistake before. Sorry.

[Wholesome]

Spoke too soon

That was just the first bug. I return again to my first question. How do I pass the reference from a DataSeries in an indicator to be indexed in a user defined method?

Is the data global? If so it could be referenced directly.

Can I pass it by name?

from:
int value = UserMethod(Value);
to:
public int UserMethod(DataSeries Value)
{
...
}

Can I pass parameters derived from the data in the indicator?

from:
double v0, v1, v2, v3;
v0 = Value[0]; v1 = Value[1]; v2 = Value[2]; v3 = Value[3];
int value = UserMethod(v0,v1,v2,v3);
to:
public int UserMethod(double v0, double v1, double v2, double v3)
{
...
}

All of these approaches compile, but none of them work.

[NinjaTrader_JoshP]

Wholesome,

What is your end game? Not following what you are trying to do.

From OnBarUpdate() you have bar information, indicator information, etc. If you have a custom method you need that information from you can pass that information in.

Create a custom method that takes parameters. Call that method with the parameters you want to pass in. Then you will have access to the values you need in that method. Then you can return back from the method to OnBarUpdate() with whatever value you want.