diff --git a/src/tests/system-tests/libs/geofunctions.cc b/src/tests/system-tests/libs/geofunctions.cc
index 8098609c1..8c1b985a0 100644
--- a/src/tests/system-tests/libs/geofunctions.cc
+++ b/src/tests/system-tests/libs/geofunctions.cc
@@ -328,17 +328,10 @@ arma::mat Euler_to_CTM(const arma::vec &eul)
     double sin_psi = sin(eul(2));
     double cos_psi = cos(eul(2));
 
-    arma::mat C = arma::zeros(3, 3);
     // Calculate coordinate transformation matrix using (2.22)
-    C(0, 0) = cos_theta * cos_psi;
-    C(0, 1) = cos_theta * sin_psi;
-    C(0, 2) = -sin_theta;
-    C(1, 0) = -cos_phi * sin_psi + sin_phi * sin_theta * cos_psi;
-    C(1, 1) = cos_phi * cos_psi + sin_phi * sin_theta * sin_psi;
-    C(1, 2) = sin_phi * cos_theta;
-    C(2, 0) = sin_phi * sin_psi + cos_phi * sin_theta * cos_psi;
-    C(2, 1) = -sin_phi * cos_psi + cos_phi * sin_theta * sin_psi;
-    C(2, 2) = cos_phi * cos_theta;
+    arma::mat C = {{cos_theta * cos_psi, cos_theta * sin_psi, -sin_theta},
+        {-cos_phi * sin_psi + sin_phi * sin_theta * cos_psi, cos_phi * cos_psi + sin_phi * sin_theta * sin_psi, sin_phi * cos_theta},
+        {sin_phi * sin_psi + cos_phi * sin_theta * cos_psi, -sin_phi * cos_psi + cos_phi * sin_theta * sin_psi, cos_phi * cos_theta}};
     return C;
 }