为什么 Amazon Forecast 无法训练预测器？

Question

While training my predictor I came across this error and I got stuck how to fix it.

I have two data-series, a "Target time-series data" with 9234 rows and a single "item_id" and a second one that is "Related time-series data" with the same number of rows as I only have a single id.

I'm setting de data with a window of 180 days, what is exactly the difference between the second and the first number that has appeared on the error, 9414 - 9234 = 180.

We were unable to train your predictor.
Please ensure there are no missing values for any items in the related time series, All items need data until 2020-03-15 00:00:00.0. For example, following items have missing data: item: brl only has 9234/9414 required datapoints starting 1994-06-07 00:00:00.0, please refer to documentation for additional details.

Once my data don't have missing data and it's on a daily basis why is it returning this error? My data starts on 1994-06-07 and ends on 2019-09-17. Why should I have 9414 data points rather than 9234? Should I take out 180 days in my "Target time-series data"?

Answer 1

The future values of the related time-series data must be known.

Example of a good related-time series: You know past and future days in which marketing has or will send email newsletters promoting the product you're forecasting. You can use this data as a related-time series.

Example of a bad related-time series: You notice that Google searches for your brand correlated with the sale of your product. As a result you want to use it as a related-time series. Since you don't know how many searches will occur in the future, so you can't use this as a related time series.

In you case, You have TARGET_TIME_SERIES data for 9414 days and you want to predict demand for the next 180 days. That means your RELATED_TIME_SERIES data should be 9594 days.

Edit: I have not tested this with amazon's forecasting product. I'm basing my answer on working with Facebook Prophet (which is one of the models amazon forcast uses). Please let me know if my solution worked.

Answer 2

just came across this thread. I had a question as it was mentioned that Related data could be used with FB prophet, which I am not aware of. Could you please guide me as to how to use related data with FB prophet. Would be really helpful.

BR, Nitin