Tools for selecting a default evaluation time

NAMESPACE

@@ -186,6 +186,8 @@ export(finalize_model)
 export(finalize_recipe)
 export(finalize_workflow)
 export(finalize_workflow_preprocessor)
+export(first_eval_time)
+export(first_metric)
 export(fit_best)
 export(fit_max_value)
 export(fit_resamples)

R/metric-selection.R

@@ -0,0 +1,51 @@
+#' Tools for selecting metrics and evaluation times
+#'
+#' @param mtr_set A [yardstick::metric_set()].
+#' @param metric A character value for which metric is being used.
+#' @param eval_time An optional vector of times to compute dynamic and/or
+#' integrated metrics.
+#' @keywords internal
+#' @export
+first_metric <- function(mtr_set) {
+  tibble::as_tibble(mtr_set)[1,]
+}
+
+#' @rdname first_metric
+#' @keywords internal
+#' @export
+first_eval_time <- function(mtr_set, metric = NULL, eval_time = NULL) {
+  num_times <- length(eval_time)
+
+  if (is.null(metric)) {
+    mtr_info <- first_metric(mtr_set)
+    metric <- mtr_info$metric
+  } else {
+    mtr_info <- tibble::as_tibble(mtr_set)
+    mtr_info <- mtr_info[mtr_info$metric == metric,]
+  }
+
+  # Not a survival metric
+  if (!any(grepl("_survival_", mtr_info$class))) {
+    return(NULL)
+  }
+
+  # Not a metric that requires an eval_time
+  no_time_req <- c("static_survival_metric", "integrated_survival_metric")
+  if (mtr_info$class %in% no_time_req) {
+    if (num_times > 0) {
+      cli::cli_warn("Evaluation times are only required when dynmanic or integrated metrics are selected as the primary metric.")
+    }
+    return(NULL)
+  }
+
+  # checks for dynamic metrics
+  if (num_times == 0) {
+    cli::cli_abort("A single evaluation time is required to use this metric.")
+  } else if ( num_times > 1 ) {
+    eval_time <- eval_time[1]
+    print_time <- format(eval_time, digits = 3)
+    cli::cli_warn("{num_times} evaluation times were available; the first ({print_time}) will be used.")
+  }
+
+  eval_time
+}

R/select_best.R

@@ -76,6 +76,8 @@ show_best.default <- function(x, ...) {
 #' @export
 #' @rdname show_best
 show_best.tune_results <- function(x, metric = NULL, n = 5, eval_time = NULL, ...) {
+  # TODO should return the as_tibble(metric_set) results to get the class etc.
+  # TODO new function start
   metric <- choose_metric(metric, x)
 
   dots <- rlang::enquos(...)
@@ -92,8 +94,12 @@ show_best.tune_results <- function(x, metric = NULL, n = 5, eval_time = NULL, ..
     metric <- metrics
   }
 
+  # TODO new function stop
+
   # get estimates/summarise
   summary_res <- summary_res %>% dplyr::filter(.metric == metric)
+
+  # TODO split selecting the req time and seeing if it is in the data
   summary_res <- choose_eval_time(summary_res, x, eval_time)
 
   if (nrow(summary_res) == 0) {
@@ -349,7 +355,8 @@ middle_eval_time <- function(x) {
   eval_time
 }
 
-
+# NOTE this chooses the time and subsets the data; break it up to only select
+# time
 choose_eval_time <- function(x, object, eval_time) {
   mtrs <- .get_tune_metrics(object)
   mtrs <- tibble::as_tibble(mtrs)

tests/testthat/_snaps/eval-time-single-selection.md

@@ -0,0 +1,44 @@
+# selecting single eval time - pure metric sets
+
+    Evaluation times are only required when dynmanic or integrated metrics are selected as the primary metric.
+
+---
+
+    Evaluation times are only required when dynmanic or integrated metrics are selected as the primary metric.
+
+---
+
+    Code
+      first_eval_time(met_dyn, eval_time = NULL)
+    Condition
+      Error in `first_eval_time()`:
+      ! A single evaluation time is required to use this metric.
+
+---
+
+    Code
+      first_eval_time(met_dyn, "brier_survival", eval_time = NULL)
+    Condition
+      Error in `first_eval_time()`:
+      ! A single evaluation time is required to use this metric.
+
+---
+
+    2 evaluation times were available; the first (0.714) will be used.
+
+# selecting single eval time - mixed metric sets - dynamic first
+
+    Code
+      first_eval_time(met_mix_dyn, eval_time = NULL)
+    Condition
+      Error in `first_eval_time()`:
+      ! A single evaluation time is required to use this metric.
+
+---
+
+    Code
+      first_eval_time(met_mix_dyn_all, eval_time = NULL)
+    Condition
+      Error in `first_eval_time()`:
+      ! A single evaluation time is required to use this metric.
+