Fix compiler warnings

include/Particle.hpp

@@ -14,14 +14,16 @@
 
 #include <armadillo>
 
+#include "typedefs.hpp"
+
 /** @brief A class that holds attributes of a particle
  * */
 class Particle {
 private:
-    double q; ///< Charge
-    double m; ///< Mass
-    arma::vec::fixed<3> r_vec; ///< position
-    arma::vec::fixed<3> v_vec; ///< velocity
+    double q;     ///< Charge
+    double m;     ///< Mass
+    vec_3d r_vec; ///< position
+    vec_3d v_vec; ///< velocity
 
 public:
     /** @brief Initialize the particle.
@@ -29,9 +31,7 @@ public:
      *  @details Initialize the particle with a charge, mass, position and
      *  velocity.
      * */
-    Particle(double q, double m, 
-             arma::vec::fixed<3> r_vec, 
-             arma::vec::fixed<3> v_vec);
+    Particle(double q, double m, vec_3d r_vec, vec_3d v_vec);
 
     /** @brief Make private attributes available for PenningTrap.
      * */