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Book Overview & Buying
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Table Of Contents
Time Series with PyTorch
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We don’t deal much with multivariate time-series forecasting in this book. Again, the calculations of the AE, SE, and APE remain similar for these types of forecasts, but they’re applied to each predicted variable. We could do this separately and take the average, or pool them much like we do for grouped individual models. There are more sophisticated approaches, such as geometric or harmonic means, but the use of them depends on your data (e.g., sensitivity to outliers).
Normalization is also crucial for assessing the error of multivariate models. So, another approach is to use distance metrics such as Euclidean or Manhattan norms. For example, the Euclidean norm (L2 norm) for the RMSE in multivariate forecasting is calculated as follows:

Where
and
are vectors of actual and forecasted values across all variables at time
. Similarly, the Manhattan norm (L1 norm) for MAE is as follows:

Choosing...