diff --git a/src/numerics.F90 b/src/numerics.F90
new file mode 100644
index 0000000..7e69eeb
--- /dev/null
+++ b/src/numerics.F90
@@ -0,0 +1,19 @@
+MODULE numerics
+    USE basic
+    USE prec_const
+    USE grid
+    USE utility
+    implicit none
+
+    COMPLEX(dp), PUBLIC, PROTECTED :: ddz_moments_i, ddzNe
+
+    PUBLIC :: compute_derivatives
+
+CONTAINS
+
+! Compute the 2D particle temperature for electron and ions (sum over Laguerre)
+SUBROUTINE compute_derivatives
+
+END SUBROUTINE compute_derivatives
+
+END MODULE numerics