Re: [amibroker] Simple code problem

["Tomasz Janeczko" <amibroker@xxxxxx>]

Title: Simple code problem

Hello,

 

You are trying to write loop code but you are using array functions (i.e. Ref). This does not make too much sense.

If you are writing looping code, you should reference previous values using subscript operators ( [] )

 

Proper way to code simple moving average from the scratch looks like this:

 

 

Periods = Param("Periods", 10, 2, 200, 1, 1 );  

result = Null; // initialize with null

// we start calculations from 'Periods' bar
// previous bars are set to null

for ( i = Periods; i < BarCount; i++ )
{
   // in the inner- loop we calculate average for last 'Periods' of bars
   tempsum = 0;
   for ( j = 0; j < Periods; j++ )
   {
      tempsum = tempsum + Close[ i - j ];
   }

   // store sum/periods in appropriate array entry
   result[ i ] = tempsum / Periods;
}

Plot( result, "MA", ParamColor( "Color", colorCycle ), ParamStyle("Style"));

Best regards,
Tomasz Janeczko
amibroker.com

----- Original Message -----

From: Rush

To: amibroker@xxxxxxxxxxxxxxx

Sent: Sunday, March 26, 2006 9:18 AM

Subject: [amibroker] Simple code problem

Hi,

This is my first attempt at using the built in language to program.  I wrote the code below, a simple moving average, which looks correct but only works correctly when “Periods” has a value of 3.  Any other value and the resulting line has a much greater value than the closing prices.  I know there are functions to do this, but I’m just trying to make an example to teach myself.

        Periods = Param("Periods", 10, 2, 200, 1, 1 ); 

        n = 0;

        for ( i = 0; i < BarCount; i++ ){

            if( i > Periods ){

                for ( j = i - (Periods-1); j <= Periods; j++ ){

                    n = n + Ref(Close,-j);

                }

            }

        }

        n = n / Periods;

        Plot( n, "MA", ParamColor( "Color", colorCycle ), ParamStyle("Style"));

However, it seems more sense to me to code it the following way, which slows the software down and also ends up with the wrong values.  Am I missing something with the way the flow of the code works in AmiBroker.

        Periods = Param("Periods", 10, 2, 200, 1, 1 );

        for ( i = 0; i < BarCount; i++ ){

            if( i > Periods ){

                n = 0;

                for ( j = Periods; j >= 0; j-- ){

                    n = n + Ref(Close,-j);

        }

                n = n / Periods;

                Plot( n, "MA", ParamColor( "Color", colorCycle ), ParamStyle("Style"));

            }

        }

Thanks

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