diff --git a/pcdet/ops/pointnet2/pointnet2_stack/src/cuda_utils.h b/pcdet/ops/pointnet2/pointnet2_stack/src/cuda_utils.h
new file mode 100644
index 0000000..c1670f1
--- /dev/null
+++ b/pcdet/ops/pointnet2/pointnet2_stack/src/cuda_utils.h
@@ -0,0 +1,9 @@
+#ifndef _STACK_CUDA_UTILS_H
+#define _STACK_CUDA_UTILS_H
+
+#include <cmath>
+
+#define THREADS_PER_BLOCK 256
+#define DIVUP(m,n) ((m) / (n) + ((m) % (n) > 0))
+
+#endif