Huber loss function

[msaca-okse]

Description

The Huber loss function behaves like the L2 loss close to 0, and like L1 loss for large values. The loss function is differentiable and can thus be used in GD or FISTA. It's an alternative to L2 loss that is more robust to extreme values

https://en.wikipedia.org/wiki/Huber_loss

Environment

import cil, sys
print(cil.version.version, cil.version.commit_hash, sys.version, sys.platform)

0.1.dev1897+g1eeb8a65b.d20260129 g1eeb8a65b 3.10.19 | packaged by conda-forge | (main, Jan 26 2026, 23:45:08) [GCC 14.3.0] linux