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Prophet: forecasting at scale

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81–90 of 114 posts

Re: Prophet: forecasting at scale

#81
So.... I don't understand how this is better or worse than using forecast.

You talk about having to choose the best algorithm but it seems like Prophet is just another algorithm to choose from. Is there some kind of built in grid-search or are you just stating that results from your AM have been more accurate than ARIMA?

Re: Prophet: forecasting at scale

#82

Earlier quoted context omitted.

Probably just help verify that the stock market is a random walk with a meager trend upwards that doesn't beat inflation + trading costs.

Some people are making pretty penny for being so random.

The same could be said about the lottery.

Re: Prophet: forecasting at scale

#83
post #79

can someone explain what's the meaning of this line > df['y'] = np.log(df['y'])

I have not read the code, but assuming df is a pandas dataframe, it sets the 'y' column to the log of what was previously the 'y' column.

https://gist.github.com/llimllib/385230f38c3f9b70c3e46158e60...

Re: Prophet: forecasting at scale

#84
This is an interesting project, and in one of the areas where almost all businesses could do better. Anecdotally, there is a ton of money left on the table by established businesses that do it poorly, which also leaves lots of room for resume-padding technical experience. So anything that claims to improve the state of the art of automated forecasting is definitely worth watching.

That being said this claim in point #1 baffles me:

> Prophet makes it much more straightforward to create a reasonable, accurate forecast. The forecast package includes many different forecasting techniques (ARIMA, exponential smoothing, etc), each with their own strengths, weaknesses, and tuning parameters. We have found that choosing the wrong model or parameters can often yield poor results, and it is unlikely that even experienced analysts can choose the correct model and parameters efficiently given this array of choices.

The forecast package contains an auto.arima function which does full parameter optimization using AIC which is just as hands free as is claimed of Prophet. I have been using it commercially and successfully for years now. Maybe prophet produces better models (I'll definitely take a look myself), but to claim that it's not possible to get good results without experience seems a bit disingenuous.

As an aside, anybody interested in a great introductory book on time series forecasting should check out Rob Hyndman's book which is freely available online. https://www.otexts.org/fpp

Re: Prophet: forecasting at scale

#85
post #49

This looks amazing, congratulations. We're planning to add forecasting to our SaaS analytics product ( https://chartmogul.com ) later this year, I'm going to look and see if we can use this in our product now.

I was trying to sort out whether adding this to an existing charting/analytics product makes sense but it looks like you've checked it out and think it does. I couldn't tell only because it seems to be built to do the charting/plotting itself, but I guess you can just use the data/API to get the forecasts then plot them yourself yes?

I may do a test implementation into Airbnb Superset actually to see how it flies.

Re: Prophet: forecasting at scale

#86

Earlier quoted context omitted.

Stan is nice but its GPL license is taboo in my corporate environment :( . I am puzzled how they managed to release Prophet under BSD with such a dependency.

Stan has a BSD core. Prophet must avoid the GPLv3 interfaces.

It doesn't avoid the R interface, which is GPL'd (version 3).

Re: Prophet: forecasting at scale

#87
post #54

Earlier quoted context omitted.

Do you know of any good beginner tutorials for Stan or probabilistic programming in general? All the examples that I found seemed quite complex and I was a bit overwhelmed by all the math. Which might also be a sign that I should brush up my math skills. What kind of math/stats should I revise to be able to better understand probabilistic programming?

Doing Bayesian Data Analysis, Second Edition: A Tutorial with R, JAGS, and Stan. It is very approachable and also has lots of practice problems. It's not a math-heavy book at all. Edit: I wouldn't recommend Probabilistic Programming and Bayesian Methods for Hackers. When I tried using it, I felt that too much was glossed over. The book that I recommend excels at conveying a strong intuition for how these various tech…

I'd second this. DBDA made things click for me where a handful of other books failed.

Re: Prophet: forecasting at scale

#88
For a corporate credit analyst working at a bank, what are some good introduction material for getting into forecasting using tools like these?

I see this being applicable to analysts when deciding on on a company's credit worthiness.

Re: Prophet: forecasting at scale

#89
post #88

For a corporate credit analyst working at a bank, what are some good introduction material for getting into forecasting using tools like these? I see this being applicable to analysts when deciding on on a company's credit worthiness.

There are some models out there which could be used but i'm not sure that forecasting is actually what you would use.

I would think if you're already assigning credit ratings, you can set that as your dependent variable and use things like company revenue, number of employees, age of company, etc. as your independent variables. You can use a number of different models to assess credit worthiness based on this data. Evaluate several to determine the most accurate.

Re: Prophet: forecasting at scale

#90
post #72

I have been working for a few years on a similar project using evolutionary algorithms on top of other models (linear / ann). It works quite well (e.g., for equidistant energy demand / supply forecasts) but there's still lots of stuff to do. It's major benefit is that it figures out relationship to the target time series by itself, so you can just throw in all time series and see what comes out. Language is Clojure,…

Why not release sooner and document the code smells? Maybe you'll get patches

I'd like to have a tested use case that mostly and simply works. Something to put in readme.md that shows how it works and that it works. Almost there...
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