Logarithm & SMA Issue

June 21st, 2011, 02:44 AM

I'm new to NinjaScript and not the world's greatest programmer so if this is a stupid question please excuse me.

I would like to plot the value of the 21 period SMA of the logarithms of the close values of each bar.

However, the Math.Log function won't let me use a DataSeries value. And the SMA function won't let me use a double value. How can I get around this.

Plot0.Set(SMA(Math.Log(Close[0])), 21)); is a no go.

Here's some simple code I tried to get around it but it didn't work. It should help illustrate the problem though.

double cl = Close[0];
double Lcl = Math.Log(cl);
DSOne.Set(Lcl);
Plot0.Set(SMA(DSOne, 21));

Any help would be greatly appreciated!

June 21st, 2011, 03:10 AM

srgtroy

I'm new to NinjaScript and not the world's greatest programmer so if this is a stupid question please excuse me.

I would like to plot the value of the 21 period SMA of the logarithms of the close values of each bar.

However, the Math.Log function won't let me use a DataSeries value. And the SMA function won't let me use a double value. How can I get around this.

Plot0.Set(SMA(Math.Log(Close[0])), 21)); is a no go.

Here's some simple code I tried to get around it but it didn't work. It should help illustrate the problem though.

double cl = Close[0];
double Lcl = Math.Log(cl);
DSOne.Set(Lcl);
Plot0.Set(SMA(DSOne, 21));

Any help would be greatly appreciated!

You need to declare a new DataSeries in the Variables section, for example

Code

private DataSeries logPrice;

then initialize this DataSeries object in the Initialize() Section

Code

logPrice = new DataSeries(this);

Then you can use it in OnBarUpdate():

Code

logPrice.Set(Math.Log(Input[0]));
Value.Set(SMA(logPrice, 21)[0]);

The point is that you need a DataSeries object to be able to apply the SMA; you cannot apply it to a variable of type double.

But what do you want to do with a SMA of the logarithm of price?

You cannot display it on the main panel, and for intraday charts you definitely do not need it.

June 22nd, 2011, 07:43 PM

Thanks for the help.

I did setup the necessary DataSeries info in the Variables and Initialize sections. That didn't turn out to be the problem. Nevertheless, you're example helped me figure it out. I noticed the first letter in logPrice was not capitalized, so I changed all the first letters I had to small caps and it worked.

Thanks, again.

Logarithm & SMA Issue

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Logarithm & SMA Issue