Effectiveness of E-prop approximation for deep, large networks on challenging tasks

Ascertain the empirical effectiveness of the E-prop approximation when performing credit assignment across both depth and time for large deep recurrent neural networks on challenging tasks.

Background

The authors derive a deep-network extension of E-prop but report no experiments. They note confidence that a full RTRL variant would match BPTT, yet emphasize uncertainty about the E-prop approximation’s performance when scaled to large, deep networks addressing difficult problems.

Single-layer E-prop has shown performance approaching BPTT on simpler tasks, leaving open whether similar behavior holds under the added complexity of both depth and long temporal dependencies.

References

While we are confident that the full RTRL variant of our algorithm would work, since it is mathematically equivalent to BPTT across both time and depth, it remains unclear how effective the E-prop approximation remains when performing credit assignment across both depth and time for large networks in challenging tasks.

Generalising E-prop to Deep Networks  (2512.24506 - Millidge, 30 Dec 2025) in Discussion