Open volomike opened 11 years ago
Looks like in your code comments you did provide a way to do a forecast. Sweet! So, anyway, I wanted to know how much this function have here differs from HW Seasonal Dampened Method, or is it just a matter of tweaking alpha, beta, and gamma?
Does this code work as intended? I tried with some values between 200 and 400 and the forecast jumped above 1300... I inputed two and a half seasons of 7 days.
Any hint appreciated...
what should be the relation/ratio between data array count and season length? did anyone figure that out?
i guess this algorithm is trying to make an output for a season length long, i only need to next item.
After i studied holt winters exponential multiplicative, i just familiar with parameter alpha, gamma and beta. But in your code, suddenly dev_gamma has appear. Could you give me an explanation about parameter dev_gamma? where do i supposted to get that value?
your website on phpir.com not aceess , i want to be a read your article bro :(
Do you know how to use Holt-Winters Seasonal Dampened Method?
Scroll to the bottom of here:
http://otexts.com/fpp/7/5/
Now, knowing that, do you know how to make a forecast in PHP? See, I'm trying to do some sales charts in a PHP app I'm building. I have year 1 and year2 data, but year2 might be partial (less than 12 months) or complete (12 months). I need to simply use Holt-Winters Seasonal Dampened Method to compute 2 months sales forecast forward.