Calculates the log-cosh loss for a set of predictions.
log(cosh(x)) is approximately (x**2) / 2 for small x and abs(x) - log(2) for large x. It is a twice differentiable alternative to the Huber loss. .. rubric:: References
[Chen et al, 2019](https://openreview.net/pdf?id=rkglvsC9Ym)
errors – a vector of arbitrary shape.
the log-cosh loss.