fix problematic argument survival in ranger models

R/kernelshap.R

@@ -359,12 +359,11 @@ kernelshap.ranger <- function(
     survival = c("chf", "prob"),
     ...
   ) {
-  survival <- match.arg(survival)
-
+
   if (is.null(pred_fun)) {
-    pred_fun <- pred_ranger
+    pred_fun <- create_ranger_pred_fun(object$treetype, survival = match.arg(survival))
   }
-  
+
   kernelshap.default(
     object = object, 
     X = X,
@@ -381,7 +380,6 @@ kernelshap.ranger <- function(
     parallel = parallel,
     parallel_args = parallel_args,
     verbose = verbose,
-    survival = survival,
     ...
   )
 }

R/permshap.R

@@ -172,12 +172,11 @@ permshap.ranger <- function(
     survival = c("chf", "prob"),
     ...
   ) {
-  survival <- match.arg(survival)
-
+
   if (is.null(pred_fun)) {
-    pred_fun <- pred_ranger
+    pred_fun <- create_ranger_pred_fun(object$treetype, survival = match.arg(survival))
   }
-  
+
   permshap.default(
     object = object,
     X = X,
@@ -188,7 +187,6 @@ permshap.ranger <- function(
     parallel = parallel,
     parallel_args = parallel_args,
     verbose = verbose,
-    survival = survival,
     ...
   )
 }

R/pred_fun.R

@@ -1,27 +1,33 @@
 #' Predict Function for Ranger
 #' 
-#' Internal function that prepares the predictions of different types of ranger models,
-#' including survival models.
+#' Returns prediction function for different modes of ranger.
 #' 
 #' @noRd
 #' @keywords internal
-#' @param model Fitted ranger model.
-#' @param newdata Data to predict on.
+#' @param treetype The value of `fit$treetype` in a fitted ranger model.
 #' @param survival Cumulative hazards "chf" (default) or probabilities "prob" per time.
-#' @param ... Additional arguments passed to ranger's predict function.
 #' 
-#' @returns A vector or matrix with predictions.
-pred_ranger <- function(model, newdata, survival = c("chf", "prob"), ...) {
+#' @returns A function with signature f(model, newdata, ...).
+create_ranger_pred_fun <- function(treetype, survival = c("chf", "prob")) {
   survival <- match.arg(survival)
 
-  pred <- stats::predict(model, newdata, ...)
+  if (treetype != "Survival") {
+    pred_fun <- function(model, newdata, ...) {
+      stats::predict(model, newdata, ...)$predictions
+    }
+    return(pred_fun)
+  }
+
+  if (survival == "prob") {
+    survival <- "survival"
+  }
 
-  if (model$treetype == "Survival") {
-    out <- if (survival == "chf") pred$chf else pred$survival
+  pred_fun <- function(model, newdata, ...) {
+    pred <- stats::predict(model, newdata, ...)
+    out <- pred[[survival]]
     colnames(out) <- paste0("t", pred$unique.death.times)
-  } else {
-    out <- pred$predictions
+    return(out)
   }
-  return(out)
+  return(pred_fun)
 }
 

backlog/test_ranger.R

@@ -0,0 +1,28 @@
+library(ranger)
+library(survival)
+library(kernelshap)
+
+set.seed(1)
+
+fit <- ranger(Surv(time, status) ~ ., data = veteran, num.trees = 20)
+fit2 <- ranger(time ~ . - status, data = veteran, num.trees = 20)
+fit3 <- ranger(time ~ . - status, data = veteran, quantreg = TRUE, num.trees = 20)
+fit4 <- ranger(status ~ . - time, data = veteran, probability = TRUE, num.trees = 20)
+
+xvars <- setdiff(colnames(veteran), c("time", "status"))
+
+kernelshap(fit, head(veteran), feature_names = xvars, bg_X = veteran)
+permshap(fit, head(veteran), feature_names = xvars, bg_X = veteran)
+
+kernelshap(fit, head(veteran), feature_names = xvars, bg_X = veteran, survival = "prob")
+permshap(fit, head(veteran), feature_names = xvars, bg_X = veteran, survival = "prob")
+
+kernelshap(fit2, head(veteran), feature_names = xvars, bg_X = veteran)
+permshap(fit2, head(veteran), feature_names = xvars, bg_X = veteran)
+
+kernelshap(fit3, head(veteran), feature_names = xvars, bg_X = veteran, type = "quantiles")
+permshap(fit3, head(veteran), feature_names = xvars, bg_X = veteran, type = "quantiles")
+
+kernelshap(fit4, head(veteran), feature_names = xvars, bg_X = veteran)
+permshap(fit4, head(veteran), feature_names = xvars, bg_X = veteran)
+