diff --git a/examples_ptx/nbody/realType.h b/examples_ptx/nbody/realType.h
new file mode 100644
index 00000000..da633473
--- /dev/null
+++ b/examples_ptx/nbody/realType.h
@@ -0,0 +1,6 @@
+#pragma once
+#if 1
+typedef double real;
+#else
+typedef float real;
+#endif