The test data is 300k different time series. There’s no way to do an arima in a reasonable amount of time and/or money on that volume of data
Though I can't quite figure out how the predicting works exactly, they have a lot of test series but do they input all of them simultaneously?
Even if true, they could take a random subset of size 100 out of the 300k and compare on those.
>Even if true, they could take a random subset of size 100 out of the 300k and compare on those.
Sure...but there's a chance that ARIMA won't even finish training on that subset either.
If you write a paper and exclude comparisons to state of the art, this what happens.
They could have done something, and didn’t.
“It’s hard so we didn’t” isn’t an excuse, it’s just a lack of rigor.