diff --git a/src/simsopt/field/tracing.py b/src/simsopt/field/tracing.py
index aece5acae..c46e1498e 100644
--- a/src/simsopt/field/tracing.py
+++ b/src/simsopt/field/tracing.py
@@ -316,7 +316,7 @@ def trace_particles_boozer(field: BoozerMagneticField, stz_inits: RealArray,
         res_ty, res_zeta_hit = sopp.particle_guiding_center_boozer_tracing(
             field, stz_inits[i, :],
             m, charge, speed_total[i], speed_par[i], tmax, vacuum=(mode == 'gc_vac'),
-            noK=(mode == 'gc_nok'), zetas=zetas, omegas=omegas, vpars=vpars,  stopping_criteria=stopping_criteria, dt_save=dt_save,
+            noK=(mode == 'gc_nok'), zetas=zetas, omegas=omegas, stopping_criteria=stopping_criteria, dt_save=dt_save, vpars=vpars, 
             **options)
         if not forget_exact_path:
             res_tys.append(np.asarray(res_ty))
diff --git a/src/simsoptpp/python_tracing.cpp b/src/simsoptpp/python_tracing.cpp
index fc3c44250..fb7c4debf 100644
--- a/src/simsoptpp/python_tracing.cpp
+++ b/src/simsoptpp/python_tracing.cpp
@@ -46,12 +46,12 @@ void init_tracing(py::module_ &m){
         py::arg("omegas")=vector<double>{},
         py::arg("stopping_criteria")=vector<shared_ptr<StoppingCriterion>>{},
         py::arg("dt_save")=1e-6,
-        py::arg("forget_exact_path")=false,
-        py::arg("axis")=0,
-        py::arg("predictor_step")=true,
+        py::arg("vpars")=vector<double>{},
         py::arg("zetas_stop")=false,
         py::arg("vpars_stop")=false,
-        py::arg("vpars")=vector<double>{}
+        py::arg("forget_exact_path")=false,
+        py::arg("axis")=0,
+        py::arg("predictor_step")=true
         );
 
     m.def("particle_guiding_center_boozer_perturbed_tracing", &particle_guiding_center_boozer_perturbed_tracing<xt::pytensor>,
diff --git a/src/simsoptpp/tracing.cpp b/src/simsoptpp/tracing.cpp
index 1ec25d2af..557d3e525 100644
--- a/src/simsoptpp/tracing.cpp
+++ b/src/simsoptpp/tracing.cpp
@@ -1201,15 +1201,14 @@ particle_guiding_center_boozer_tracing(
         shared_ptr<BoozerMagneticField<T>> field, array<double, 3> stz_init,
         double m, double q, double vtotal, double vtang, double tmax, double dt, double abstol, double reltol, double roottol,
         bool vacuum, bool noK, bool solveSympl, vector<double> zetas, vector<double> omegas,
-        vector<shared_ptr<StoppingCriterion>> stopping_criteria, double dt_save, bool forget_exact_path, int axis, bool predictor_step,
-        bool zetas_stop, bool vpars_stop, vector<double> vpars)
+        vector<shared_ptr<StoppingCriterion>> stopping_criteria,  double dt_save, vector<double> vpars,
+        bool zetas_stop, bool vpars_stop, bool forget_exact_path, int axis, bool predictor_step)
 {
     typename BoozerMagneticField<T>::Tensor2 stz({{stz_init[0], stz_init[1], stz_init[2]}});
     field->set_points(stz);
     double modB = field->modB()(0);
     double vperp2 = vtotal*vtotal - vtang*vtang;
     double mu = vperp2/(2*modB);
-
     array<double, 4> y;
 
     double G0 = std::abs(field->G()(0));
@@ -1273,6 +1272,9 @@ particle_guiding_center_boozer_perturbed_tracing<xt::pytensor>(
         double omega, int Phim, int Phin, double phase, bool forget_exact_path, int axis, vector<double> vpars);
 
 template
-tuple<vector<array<double, 5>>, vector<array<double, 6>>>
-particle_guiding_center_boozer_tracing<xt::pytensor>(
-        shared_ptr<BoozerMagneticField<xt::pytensor>> field, array<double, 3> stz_init, double m, double q, double vtotal, double vtang, double tmax, double dt, double abstol, double reltol, double roottol, bool vacuum, bool noK, bool solveSympl, vector<double> zetas, vector<double> omegas, vector<shared_ptr<StoppingCriterion>> stopping_criteria, double dt_save, bool forget_exact_path, int axis, bool predictor_step, bool zetas_stop, bool vpars_stop, vector<double> vpars);
\ No newline at end of file
+tuple<vector<array<double, 5>>, vector<array<double, 6>>> particle_guiding_center_boozer_tracing<xt::pytensor>(
+        shared_ptr<BoozerMagneticField<xt::pytensor>> field, array<double, 3> stz_init,
+        double m, double q, double vtotal, double vtang, double tmax, double dt, double abstol, double reltol, double roottol,
+        bool vacuum, bool noK, bool solveSympl, vector<double> zetas, vector<double> omegas,
+        vector<shared_ptr<StoppingCriterion>> stopping_criteria, double dt_save,
+        vector<double> vpars, bool zetas_stop, bool vpars_stop, bool forget_exact_path, int axis, bool predictor_step);
\ No newline at end of file
diff --git a/src/simsoptpp/tracing.h b/src/simsoptpp/tracing.h
index e51ba972e..068ab639b 100644
--- a/src/simsoptpp/tracing.h
+++ b/src/simsoptpp/tracing.h
@@ -114,12 +114,10 @@ particle_guiding_center_boozer_perturbed_tracing(
         double alphahat=0, double omega=0, int alpham=0, int alphan=0, double phase=0,
         bool forget_exact_path=false, int axis=0, vector<double> vpars={});
 
-	template<template<class, std::size_t, xt::layout_type> class T>
-	tuple<vector<array<double, 5>>, vector<array<double, 6>>>
-	particle_guiding_center_boozer_tracing(
-			  shared_ptr<BoozerMagneticField<T>> field, array<double, 3> stz_init,
+template<template<class, std::size_t, xt::layout_type> class T>
+tuple<vector<array<double, 5>>, vector<array<double, 6>>>
+particle_guiding_center_boozer_tracing(
+        shared_ptr<BoozerMagneticField<T>> field, array<double, 3> stz_init,
         double m, double q, double vtotal, double vtang, double tmax, double dt, double abstol, double reltol, double roottol,
-        bool vacuum, bool noK, bool solveSympl, vector<double> zetas, vector<double> omegas, vector<shared_ptr<StoppingCriterion>> stopping_criteria, double dt_save = 1e-6,
-        bool forget_exact_path=false, int axis=0, bool predictor_step=true,
-        bool zetas_stop=false, bool vpars_stop=false, vector<double> vpars={});
-
+        bool vacuum, bool noK, bool solveSympl, vector<double> zetas, vector<double> omegas,
+        vector<shared_ptr<StoppingCriterion>> stopping_criteria, double dt_save, vector<double> vpars, bool zetas_stop=false, bool vpars_stop=false, bool forget_exact_path=false, int axis=0, bool predictor_step=true);