Seeking coding solution â€“ NinjaTrader

December 22nd, 2014, 06:56 AM

Hello Coders,

I made an indicator that colors bars with a smaller open to close range than the previous 3 bars. I used this code:

Code

if( Close[0] > Open[0] && Math.Abs(Close[0] - Open[0]) < Math.Abs(Close[1] - Open[1]) && Math.Abs(Close[0] - Open[0]) < Math.Abs(Close[2] - Open[2]) && Math.Abs(Close[0] - Open[0]) < Math.Abs(Close[3] – Open[3]))

else if( Close[0] <= Open[0] && Math.Abs(Close[0] - Open[0]) <= Math.Abs(Close[1] - Open[1]) && Math.Abs(Close[0] - Open[0]) <= Math.Abs(Close[2] - Open[2]) && Math.Abs(Close[0] - Open[0]) <= Math.Abs(Close[3] – Open[3]))

I like now to improve that indicator by adding a selectable look back period and made these changes:

Code

#region Variables:
private int		barsback	=	3;

OnBarUpdate():
if (CurrentBar < barsback+1)	
{ return; }

for (int j=1; j<=barsback; j++)

if( Close[0] > Open[0] && Math.Abs(Close[0] - Open[0]) <= Math.Abs(Close[j] – Open[j]))

else if( Close[0] <= Open[0] && Math.Abs(Close[0] - Open[0]) <= Math.Abs(Close[j] – Open[j]))

Unfortunately that didn´t work and it colors every bar, with a smaller open to close range than the entire selected look back period
(see attached chart). What I´m doing wrong here?

Many thanks in advance for every tip.

December 22nd, 2014, 01:56 PM

It colors every bar because the code does not keep in mind the prior result. Basically your condition would be false, if there is a single bar within the lookback period "barsback" that has a smaller body then the current bar. A workaround would be to use a boolean variable "narrowBody", set that variable to true, and then loop through the prior bars. In case that you find a single bar that has a smaller body than the current bar you may set the boolean to false and exit the loop:

Code

bool narrowBodyBar = true;
double bodyRange = Math.Abs(Close[0] - Open[0]);
for int j = 1; j <= barsBack; j++)
   if(Math.Abs(Close[j]-Open[j]) < bodyRange)
   {
         narrowBodyBar=false;
         break;  //to exit loop, as the condition narrowBodyBar cannot come true anymore
   }

The baisc logic of the indicator - detecting a narrow range - requires that it runs in mode "CalculateOnBarClose = true". If you wish to run it in "CalculateOnBarClose = false" to get a preliminary result, then the code above would be highly inefficient, as you would need to run through the entire loop with every incoming tick. Therefore to make the indicator efficient for use with "CalculateOnBarClose = false" you would need to modify the code, for example:

Code

#region  Variables
double minBody = 0.0;
bool narrowBodyBar = false;
#endregion

// within OnBarUpdate
if(FirstTickOfBar) // executed once per bar
{
    minBody = Math.Abs(Close[1] - Open[1])
    for (int j = 2; j <= barsBack; j++)
        if(Math.Abs(Close[j] - Open[j]) < minBody)
             minBody = Math.Abs(Close[j] - Open[j]);
}
if (Math.Abs(Close[0] - Open[0]) <= minBody) // executed with every incoming tick
   narrowBodyBar = true;

Not tested.

December 22nd, 2014, 02:47 PM

Fat Tails

It colors every bar because the code does not keep in mind the prior result. Basically your condition would be false, if there is a single bar within the lookback period "barsback" that has a smaller body then the current bar. A workaround would be to use a boolean variable "narrowBody", set that variable to true, and then loop through the prior bars. In case that you find a single bar that has a smaller body than the current bar you may set the boolean to false and exit the loop:

Code

bool narrowBodyBar = true;
double bodyRange = Math.Abs(Close[0] - Open[0]);
for int j = 1; j <= barsBack; j++)
   if(Math.Abs(Close[j]-Open[j]) < bodyRange)
   {
         narrowBodyBar=false;
         break;  //to exit loop, as the condition narrowBodyBar cannot come true anymore
   }

The baisc logic of the indicator - detecting a narrow range - requires that it runs in mode "CalculateOnBarClose = true". If you wish to run it in "CalculateOnBarClose = false" to get a preliminary result, then the code above would be highly inefficient, as you would need to run through the entire loop with every incoming tick. Therefore to make the indicator efficient for use with "CalculateOnBarClose = false" you would need to modify the code, for example:

Code

#region  Variables
double minBody = 0.0;
bool narrowBodyBar = false;
#endregion

// within OnBarUpdate
if(FirstTickOfBar) // executed once per bar
{
    minBody = Math.Abs(Close[1] - Open[1])
    for (int j = 2; j <= barsBack; j++)
        if(Math.Abs(Close[j] - Open[j]) < minBody)
             minBody = Math.Abs(Close[j] - Open[j]);
}
if (Math.Abs(Close[0] - Open[0]) <= minBody) // executed with every incoming tick
   narrowBodyBar = true;

Not tested.

@Fat Tails

Many Thanks for your help Harry!

It makes no sense to run this indicator in mode "CalculateOnBarClose = false. I will try therefore your first code.
Does the complete code goes to the "OnBarUpdate()" section?

December 22nd, 2014, 04:22 PM

Abde

@Fat Tails

Many Thanks for your help Harry!

It makes no sense to run this indicator in mode "CalculateOnBarClose = false. I will try therefore your first code.
Does the complete code goes to the "OnBarUpdate()" section?

The first example should be included with OnBarUpdate().

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