Error checking for LiblineaR type and mode

Author: juliasilge

R/svm_linear.R

@@ -146,10 +146,31 @@ translate.svm_linear <- function(x, engine = x$engine, ...) {
 
   if (x$engine == "LiblineaR") {
 
-    if (x$mode == "regression")
+    if (is_null(x$eng_args$type)) {
+      liblinear_type <- NULL
+    } else {
+      liblinear_type <- quo_get_expr(x$eng_args$type)
+    }
+
+    if (x$mode == "regression") {
       if (is_null(quo_get_expr(x$args$margin)))
         arg_vals$svr_eps <- 0.1
-
+      if (!is_null(liblinear_type))
+        if(!liblinear_type %in% 11:13)
+          rlang::abort(
+            paste0("The LiblineaR engine argument of `type` = ",
+                   liblinear_type,
+                   " does not correspond to an SVM regression model.")
+          )
+    } else if (x$mode == "classification") {
+      if (!is_null(liblinear_type))
+        if(!liblinear_type %in% 1:5)
+          rlang::abort(
+            paste0("The LiblineaR engine argument of `type` = ",
+                   liblinear_type,
+                   " does not correspond to an SVM classification model.")
+          )
+    }
   }
 
   x$method$fit$args <- arg_vals

tests/testthat/test_svm_linear.R

@@ -76,6 +76,8 @@ test_that('updating', {
 test_that('bad input', {
   expect_error(svm_linear(mode = "reallyunknown"))
   expect_error(translate(svm_linear(mode = "regression") %>% set_engine( NULL)))
+  expect_error(translate(svm_linear(mode = "regression") %>% set_engine("LiblineaR", type = 3)))
+  expect_error(translate(svm_linear(mode = "classification") %>% set_engine("LiblineaR", type = 11)))
 })
 
 # ------------------------------------------------------------------------------