confirm working on ubuntu
diff --git a/.Rproj.user/441ADA46/cpp-definition-cache b/.Rproj.user/441ADA46/cpp-definition-cache
new file mode 100644
index 0000000..32960f8
--- /dev/null
+++ b/.Rproj.user/441ADA46/cpp-definition-cache
@@ -0,0 +1,2 @@
+[
+]
\ No newline at end of file