Calculate EMA using SV's/History lists
Hi. Was advised by support to post this request here. As an exercise (maybe in futility but should be fun to try anyway ) I would like to be able to calculate the EMA (like the one you can add to charts) using SV's and/or history lists (variable periods) for use in horse racing (back,lay or LTP-not fussed.) I have had a go myself but can't seem to get it right. Any help to create a baf appreciated. Cheers
- ShaunWhite
- Posts: 9731
- Joined: Sat Sep 03, 2016 3:42 am
EMA = Closing price x multiplier + EMA (previous day) x (1-multiplier)
So, the multiplier can be a constant or a simple calc, it's just
[2 ÷ (number of observations + 1)]
Then at the required frequency .....
EMA = price x multiplier + EMAprev x (1-multiplier)
EMAprev = EMA
..and repeat
The calc only needs to remember the prev EMA not a whole history. The shorter the number of observations, the larger the multiplier, and that gives more weight to the current price (the price x multiplier part) than the previous EMA (the EMAprev x (1-multiplier) part). Long observations, smaller muliplier, opposite effect.
You'll need to translate that into Guardianese. That part is beyond my pay grade Hope it helps.
So, the multiplier can be a constant or a simple calc, it's just
[2 ÷ (number of observations + 1)]
Then at the required frequency .....
EMA = price x multiplier + EMAprev x (1-multiplier)
EMAprev = EMA
..and repeat
The calc only needs to remember the prev EMA not a whole history. The shorter the number of observations, the larger the multiplier, and that gives more weight to the current price (the price x multiplier part) than the previous EMA (the EMAprev x (1-multiplier) part). Long observations, smaller muliplier, opposite effect.
You'll need to translate that into Guardianese. That part is beyond my pay grade Hope it helps.
Last edited by ShaunWhite on Fri Jan 27, 2023 1:57 am, edited 1 time in total.