R/estimatorhelpers.R
, R/probhelpers.R
, R/validation.R
developerhelpers.Rd
Helpers to be used alongside metric_vec_template()
and metric_summarizer()
when creating new metrics. See vignette("custommetrics", "yardstick")
for
more information.
get_weights(data, estimator) finalize_estimator(x, estimator = NULL, metric_class = "default") finalize_estimator_internal(metric_dispatcher, x, estimator) dots_to_estimate(data, ...) validate_estimator(estimator, estimator_override = NULL)
data  A table with truth values as columns and predicted values as rows. 

estimator  Either 
x  The column used to autoselect the estimator. This is generally
the 
metric_class  A single character of the name of the metric to autoselect
the estimator for. This should match the method name created for

metric_dispatcher  A simple dummy object with the class provided to

...  A set of unquoted column names or one or more

estimator_override  A character vector overriding the default allowed
estimator list of 
get_weights()
accepts a confusion matrix and an estimator
of type
"macro"
, "micro"
, or "macro_weighted"
and returns the correct weights.
It is useful when creating multiclass metrics.
finalize_estimator()
is the engine for autoselection of estimator
based
on the type of x
. Generally x
is the truth
column. This function
is called from the vector method of your metric.
finalize_estimator_internal()
is an S3 generic that you should extend for
your metric if it does not implement only the following estimator types:
"binary"
, "macro"
, "micro"
, and "macro_weighted"
. If your metric
does support all of these, the default version of
finalize_estimator_internal()
will autoselect estimator
appropriately.
If you need to create a method, it should take the form:
finalize_estimator_internal.metric_name
. Your method for
finalize_estimator_internal()
should do two things:
If estimator
is NULL
, autoselect the estimator
based on the
type of x
and return a single character for the estimator
.
If estimator
is not NULL
, validate that it is an allowed estimator
for your metric and return it.
If you are using the default for finalize_estimator_internal()
, the
estimator
is selected using the following heuristics:
If estimator
is not NULL
, it is validated and returned immediately
as no autoselection is needed.
If x
is a:
factor
 Then "binary"
is returned if it has 2 levels, otherwise
"macro"
is returned.
numeric
 Then "binary"
is returned.
table
 Then "binary"
is returned if it has 2 columns, otherwise
"macro"
is returned. This is useful if you have table
methods.
matrix
 Then "macro"
is returned.
dots_to_estimate()
is useful with class probability metrics that take
...
rather than estimate
as an argument. It constructs either a single
name if 1 input is provided to ...
or it constructs a quosure where the
expression constructs a matrix of as many columns as are provided to ...
.
These are eventually evaluated in the summarise()
call in
metric_summarizer()
and evaluate to either a vector or a matrix for further
use in the underlying vector functions.
validate_estimator()
is called from your metric specific method of
finalize_estimator_internal()
and ensures that a user provided estimator
is of the right format and is one of the allowed values.