Create a different evaluation metric from a valid Keras metric
evaluation_metric(evaluate_f)Must be either a metric function defined by Keras (e.g.
keras::metric_binary_crossentropy) or a valid function for Keras to
create a performance metric (see \link[keras]{metric_binary_accuracy}
for details)
A function which can be called with parameters learner and data
just like the ones defined in \link[ruta]{evaluate}.
\link[ruta]{evaluate}