diff --git a/src/utils_trust_region/pi.h b/src/utils_trust_region/pi.h
new file mode 100644
index 00000000..2c36a9f0
--- /dev/null
+++ b/src/utils_trust_region/pi.h
@@ -0,0 +1,2 @@
+  logical, parameter :: debug=.False.
+  double precision, parameter :: pi = 3.1415926535897932d0