diff --git a/include/BSMPT/utility/const_velocity_spline.h b/include/BSMPT/utility/const_velocity_spline.h
index c2add41f7..2f4429f80 100644
--- a/include/BSMPT/utility/const_velocity_spline.h
+++ b/include/BSMPT/utility/const_velocity_spline.h
@@ -189,12 +189,12 @@ class cvspline
    * @param l
    * @return std::vector<double>
    */
-  std::vector<double> operator()(double l);
+  std::vector<double> operator()(double l) const;
   /**
    * @brief print the current knots of the spline
    *
    */
-  void print_path();
+  void print_path() const;
   /**
    * @brief save the knots of the splien into a file
    *
diff --git a/src/utility/const_velocity_spline.cpp b/src/utility/const_velocity_spline.cpp
index c10b36f42..907e39d55 100644
--- a/src/utility/const_velocity_spline.cpp
+++ b/src/utility/const_velocity_spline.cpp
@@ -266,7 +266,7 @@ std::vector<double> cvspline::d2l(double l)
 
   return rr;
 }
-std::vector<double> cvspline::operator()(double l)
+std::vector<double> cvspline::operator()(double l) const
 {
   // Calculates the VEV at the position l in spline length,
   l = l_to_x(l); // Convert from spline length to linear length.
@@ -278,7 +278,7 @@ std::vector<double> cvspline::operator()(double l)
   return r;
 }
 
-void cvspline::print_path()
+void cvspline::print_path() const
 {
   int wid = 15;
 
diff --git a/standalone/TunnelingPath.cpp b/standalone/TunnelingPath.cpp
index 1954a8627..552aeb127 100644
--- a/standalone/TunnelingPath.cpp
+++ b/standalone/TunnelingPath.cpp
@@ -77,10 +77,10 @@ int main()
     bounce.CalculatePercolationTemp();
     if (bounce.GetPercolationTemp() == -1) continue;
     double errorTtoTp = 1e100;
-    BounceActionInt *ClosestBounceActionInt;
+    BounceActionInt const *ClosestBounceActionInt;
     std::cout << "Found a transitions with Tp =\t"
               << bounce.GetPercolationTemp() << " GeV.\n";
-    for (auto BAInt : bounce.SolutionList)
+    for (const auto &BAInt : bounce.SolutionList)
     {
       if (abs(BAInt.T - bounce.GetPercolationTemp()) < errorTtoTp)
       {