exponential moving averages

[Gene]

I'm having trouble getting the same ema (17 period) as displayed by esignal on a 1hr bar.

The current price is 16.46
The last ema-17 was 16.24

I'm multiplying 16.46 times 2/18

and adding it to

16.24 times 16/18

and coming up with 16.249

esig is coming up with 16.268

The stock is LTD, Date 09/18/03 10:30am price 16.46

If someone could explain how I could get the same results esig does it would save me from pulling out my hair. Thanks !

[eSignal_JasonK]

Hello Gene,


In our EFS library, there is a help example that will show you how to code the EMA calculation (EMAcalc.efs). See the first post in that thread. The chart below displays the 17 ema of the EFScalc.efs and the built-in EMA study. The dark green line is the EFS.

[Gene]

thanks, but...

I'm not using EFS, so I'm afraid the EFS example is just confusing things for me. I'm not understanding at all why the math I'm using doesn't come up with the same number that appears on the Esig chart.



I'm pretty sure the formula is corect and I'm assuming I'm coming up with a different answer because I'm selecting different prices than Esig is, but, I can't find my error.

Am I using the wrong 'last ema17' ? in my calculation ?

Can you tell me exactly what numbers you are actually using to come up with the ema17 that you are in the example I gave, which would tell me why I'm getting a different result ?

[eSignal_JasonK]

Hello Gene,

No problem. Let's see if I can help clear this up for you. For this example we have the following data:

close = 16.46
dPercent = (2.0/ Length +1) = (2.0/18) = 0.1111
last ema17 = 16.2444

EMA-17 = ((close - last ema17) * dPercent) + last ema17

EMA-17 = ((16.46 - 16.2444) * 0.1111) + 16.2444

EMA-17 = 16.2684

[Gene]

Thanks

That seems to work, thanks for saving me a lot of time.