fix batch_size param

.gitignore

@@ -17,4 +17,5 @@ CRAN-SUBMISSION
 paper/data
 .idea/
 .vsc/
-paper/data
+paper/data
+.vscode

R/LearnerTorch.R

@@ -532,7 +532,20 @@ LearnerTorch = R6Class("LearnerTorch",
         "worker_packages"
       )
       args = param_vals[names(param_vals) %in% dl_args]
-      for(param_name in c("sampler", "batch_sampler")){
+
+      ok = sum(is.null(args$sampler), is.null(args$batch_sampler), is.null(args$batch_size)) == 2L
+
+      if (!ok) {
+        stopf("Provide either 'sampler', 'batch_sampler', or 'batch_size'.")
+      }
+
+      if (is.null(args$batch_size)) {
+        if (!is.null(args$shuffle) || !is.null(args$drop_last)) {
+          stopf("'shuffle' and 'drop_last' are only allowed when 'batch_size' is provided.")
+        }
+      }
+
+      for (param_name in c("sampler", "batch_sampler")){
         param_val <- args[[param_name]]
         if (!is.null(param_val)) {
           # instantiate these params which should be classes.
@@ -542,6 +555,9 @@ LearnerTorch = R6Class("LearnerTorch",
       invoke(dataloader, dataset = dataset, .args = args)
     },
     .dataloader_predict = function(dataset, param_vals) {
+      if (is.null(param_vals$batch_size)) {
+        stop("'batch_size' must be provided for prediction.")
+      }
       param_vals_test = insert_named(param_vals, list(shuffle = FALSE, drop_last = FALSE))
       private$.dataloader(dataset, param_vals_test)
     },

R/paramset_torchlearner.R

@@ -71,10 +71,14 @@ paramset_torchlearner = function(task_type, jittable = FALSE) {
     patience              = p_int(lower = 0L, tags = c("train", "required"), init = 0L),
     min_delta             = p_dbl(lower = 0, tags = c("train", "required"), init = 0),
     # dataloader parameters
-    batch_size            = p_int(tags = c("train", "predict", "required"), lower = 1L),
+    batch_size            = p_int(tags = c("train", "predict"), lower = 1L),
     shuffle               = p_lgl(tags = "train", default = FALSE, init = TRUE),
-    sampler               = p_uty(tags = c("train", "predict")),
-    batch_sampler         = p_uty(tags = c("train", "predict")),
+    sampler               = p_uty(tags = c("train", "predict"), custom_check = crate(function(x) {
+      checkmate::check_class(x, "torch_sampler")
+    })),
+    batch_sampler         = p_uty(tags = c("train", "predict"), custom_check = crate(function(x) {
+      checkmate::check_class(x, "torch_sampler")
+    })),
     num_workers           = p_int(lower = 0, default = 0, tags = c("train", "predict")),
     collate_fn            = p_uty(tags = c("train", "predict"), default = NULL),
     pin_memory            = p_lgl(default = FALSE, tags = c("train", "predict")),