metrics.md
In luz: Higher Level 'API' for 'torch'

get a nice error message when metric fails updating

Error while calling callback with class <metrics_callback/LuzCallback/R6> at on_train_batch_end.
Caused by error in `FUN()`:
! Error when evaluating update for metric with abbrev "h" and class <hello/LuzMetric/R6>
i The error happened at iter 1 of epoch 1.
i The model was in training mode.
Caused by error in `metric$update()`:
! error in metric!

error gracefully on failed `compute`.

Error while calling callback with class <metrics_callback/LuzCallback/R6> at on_train_end.
Caused by error in `self$call_compute_on_metric()`:
! Error when evaluating compute for metric with abbrev "h" and class <hello/LuzMetric/R6>
i The error happened at iter 31 of epoch 1.
i The model was in training mode.
Caused by error in `metric$compute()`:
! Error computing metric.