diff --git a/DESCRIPTION b/DESCRIPTION
index a0209353..444f25f3 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: aorsf
 Title: Accelerated Oblique Random Survival Forests
-Version: 0.1.1
+Version: 0.1.1.9001
 Authors@R: c(
     person(given = "Byron",
            family = "Jaeger",
diff --git a/NEWS.md b/NEWS.md
index 42380d32..ae4f0f8e 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,7 @@
+# aorsf 0.1.1.9000
+
+* optimization implemented for matrix multiplication during prediction (https://github.com/ropensci/aorsf/pull/20)
+
 # aorsf 0.1.1
 
 * fixed an uninitialized value for `pd_type`
diff --git a/R/infer.R b/R/infer.R
index 727865b2..075c5bd7 100644
--- a/R/infer.R
+++ b/R/infer.R
@@ -34,3 +34,42 @@ infer_pred_horizon <- function(object, pred_type, pred_horizon){
  pred_horizon
 
 }
+
+
+#' helper for guessing outcome type
+#'
+#' @param names_y_data character vector of outcome names
+#' @param data dataset containing outcomes
+#'
+#' @return character value: 'survival', 'regression' or 'classification'
+#'
+#' @examples
+#'
+#' infer_outcome_type('bili', pbc_orsf)
+#' infer_outcome_type('sex', pbc_orsf)
+#' infer_outcome_type(c('time', 'status'), pbc_orsf)
+#' infer_outcome_type(Surv(pbc_orsf$time, pbc_orsf$status), pbc_orsf)
+#'
+#' @noRd
+infer_outcome_type <- function(names_y_data, data){
+
+ if(length(names_y_data) > 2){
+  stop("formula should have at most two variables as the response",
+       call. = FALSE)
+ }
+
+ if(length(names_y_data) == 2) {
+  return("survival")
+ }
+
+ if(is.factor(data[[names_y_data]])){
+  return("classification")
+ } else if(inherits(data[[names_y_data]], 'Surv')) {
+  return("survival")
+ } else {
+  return("regression")
+ }
+
+ stop("could not infer outcome type", call. = FALSE)
+
+}
diff --git a/R/orsf.R b/R/orsf.R
index 24a8df11..453fef60 100644
--- a/R/orsf.R
+++ b/R/orsf.R
@@ -491,7 +491,6 @@ orsf <- function(data,
  net_alpha <- control_net$net_alpha
  net_df_target <- control_net$net_df_target
 
-
  formula_terms <- suppressWarnings(stats::terms(formula, data=data))
 
  if(attr(formula_terms, 'response') == 0)
@@ -499,20 +498,14 @@ orsf <- function(data,
 
  names_y_data <- all.vars(formula[[2]])
 
- if(length(names_y_data) == 1){
-  # this is fine if the response is a Surv object,
-  if(!inherits(data[[names_y_data]], 'Surv')){
-   # otherwise it will be a problem
-   stop("formula must have two variables (time & status) as the response",
-        call. = FALSE)
-  }
+ outcome_type <- infer_outcome_type(names_y_data, data)
 
- }
+ if(outcome_type %in% c('regression', 'classification')) stop("not ready yet")
 
- if(length(names_y_data) > 2){
-  stop("formula must have two variables (time & status) as the response",
-       call. = FALSE)
- }
+ tree_type_R = switch(outcome_type,
+                      'classification' = 1,
+                      'regression'= 2,
+                      'survival' = 3)
 
  types_y_data <- vector(mode = 'character',
                         length = length(names_y_data))
@@ -741,9 +734,7 @@ orsf <- function(data,
   tree_seeds <- sample(x = n_tree*10, size = n_tree, replace = FALSE)
  }
 
-
  vi_max_pvalue = 0.01
- tree_type_R = 3
 
  orsf_out <- orsf_cpp(x = x_sort,
                       y = y_sort,
diff --git a/src/orsf_oop.cpp b/src/orsf_oop.cpp
index ec9d836f..cf90e38a 100644
--- a/src/orsf_oop.cpp
+++ b/src/orsf_oop.cpp
@@ -283,6 +283,15 @@
   // re-cast integer inputs from R into enumerations
   // see globals.h for definitions.
   TreeType tree_type = (TreeType) tree_type_R;
+
+  if(tree_type == TREE_CLASSIFICATION ||
+     tree_type == TREE_PROBABILITY ||
+     tree_type == TREE_REGRESSION){
+
+   stop("that tree type is not ready yet");
+
+  }
+
   VariableImportance vi_type = (VariableImportance) vi_type_R;
   SplitRule split_rule = (SplitRule) split_rule_R;
   LinearCombo lincomb_type = (LinearCombo) lincomb_type_R;
diff --git a/tests/testthat/test-infer.R b/tests/testthat/test-infer.R
index 0b6e76dd..efb1c428 100644
--- a/tests/testthat/test-infer.R
+++ b/tests/testthat/test-infer.R
@@ -38,4 +38,16 @@ test_that(
 )
 
 
+test_that(
+ desc = 'inferred outcome type is correct',
+ code = {
+
+  pbc$surv_y <- Surv(pbc_orsf$time, pbc_orsf$status)
 
+  expect_equal(infer_outcome_type(c('time', 'status'), pbc), 'survival')
+  expect_equal(infer_outcome_type('surv_y', pbc), 'survival')
+  expect_equal(infer_outcome_type('age', pbc), 'regression')
+  expect_equal(infer_outcome_type('sex', pbc), 'classification')
+
+ }
+)
diff --git a/tests/testthat/test-orsf_formula.R b/tests/testthat/test-orsf_formula.R
index 7303c31c..d7e2ba04 100644
--- a/tests/testthat/test-orsf_formula.R
+++ b/tests/testthat/test-orsf_formula.R
@@ -28,10 +28,7 @@ test_that(
                'not_right')
 
   expect_error(orsf(pbc_orsf, Surv(start, time, status) ~ .),
-               'must have two variables')
-
-  expect_error(orsf(pbc_orsf, Surv(time, time) ~ . - id),
-               'must have two variables')
+               'should have at most two variables')
 
   expect_error(orsf(pbc_orsf, Surv(time, id) ~ . -id),
                'detected >1 event type')