Revert "implement future.apply in forecast.mdl_df"

This reverts commit d49e0ab.

It causes issues with evaluation flow, and it is more valuable to parallelise across series rather than models

R/forecast.R

@@ -105,38 +105,13 @@ forecast.mdl_df <- function(object, new_data = NULL, h = NULL,
     object <- bind_new_data(object, new_data)
   }
 
-  object <- tidyr::pivot_longer(object, !!mdls, names_to = ".model", values_to = ".mdl")
-
   # Evaluate forecasts
-  if(is_attached("package:future")){
-    require_package("future.apply")
-
-    object[[".fc"]] <- future.apply::future_mapply(
-      FUN = forecast,
-      object[[".mdl"]],
-      MoreArgs = list(
-        h = h, 
-        point_forecast = point_forecast,
-        ...,
-        key_data = key_data(object)
-      ),
-      SIMPLIFY = FALSE,
-      future.globals = FALSE
-    )
-  }
-  else{
-    object[[".fc"]] <- mapply(
-      FUN = forecast,
-      object[[".mdl"]],
-      MoreArgs = list(
-        h = h, 
-        point_forecast = point_forecast,
-        ...,
-        key_data = key_data(object)
-      ),
-      SIMPLIFY = FALSE
-    )
-  }
+  object <- dplyr::mutate_at(as_tibble(object), vars(!!!mdls),
+                             forecast, object[["new_data"]],
+                             h = h, point_forecast = point_forecast, ...,
+                             key_data = key_data(object))
+
+  object <- tidyr::pivot_longer(object, !!mdls, names_to = ".model", values_to = ".fc") 
 
   # Combine and re-construct fable
   fbl_attr <- attributes(object$.fc[[1]])