diff --git a/functions.cpp b/functions.cpp
index a0d3cca..13c5fed 100644
--- a/functions.cpp
+++ b/functions.cpp
@@ -15,6 +15,9 @@ int nearest_index(const std::vector<double> &x_ref, const double x, int start=0)
 }
 
 double lerp(const std::vector<double>& x_ref, const std::vector<double>& y_ref, const double x, const int i) {
+    /*
+     * Linear interpolation between two
+     */
     const double x_left = x_ref[i];
     const double y_left = y_ref[i];
     const double x_right = x_ref[i+1];
@@ -26,6 +29,9 @@ double lerp(const std::vector<double>& x_ref, const std::vector<double>& y_ref,
 }
 
 std::chrono::time_point<std::chrono::system_clock> printSteps(
+    /*
+     * Prints roughly every 10 seconds how many runs were done and gives a time estimation
+     */
     const std::chrono::time_point<std::chrono::system_clock> last_print_out,
     const std::chrono::time_point<std::chrono::system_clock> start,
     const int total,
@@ -37,15 +43,11 @@ std::chrono::time_point<std::chrono::system_clock> printSteps(
         return last_print_out;
     }
 
-    std::chrono::duration<float> duration = now - start;
+    const std::chrono::duration<float> duration = now - start;
     const auto passed = duration.count();
 
 
     std::cout << steps << " of " << total << " steps: " << passed << "s passed; ~" << passed * static_cast<float>(total-steps) / static_cast<float>(steps) << "s remaining\n";
 
     return now;
-    // time_t end_time = std::chrono::system_clock::to_time_t(end);
-    // std::cout << "End   tau = " << tau_i << "s : " << ctime(&end_time);
-    // std::cout << "Duration: " << duration.count() << "s\n" << std::endl;
-
 }
\ No newline at end of file
diff --git a/io.cpp b/io.cpp
index 859a5f7..1dcb038 100644
--- a/io.cpp
+++ b/io.cpp
@@ -12,9 +12,15 @@
 #include <unordered_map>
 #include <map>
 #include <string>
+#include <filesystem>
 
 
-std::unordered_map<std::string, double> parse_arguments(const char *infile) {
+std::unordered_map<std::string, double> parse_arguments(const std::filesystem::path& infile) {
+    if (!std::filesystem::exists(infile)) {
+        std::cerr << "File " << infile << " does not exist" << std::endl;
+        exit(1);
+    }
+
     std::ifstream instream(infile);
 
     std::unordered_map<std::string, double> parameter;
@@ -25,8 +31,6 @@ std::unordered_map<std::string, double> parse_arguments(const char *infile) {
     std::string value;
     size_t delim_pos;
 
-    // TODO this needs a check for file existence
-
     while (std::getline(instream, line)) {
         line.erase(std::remove(line.begin(), line.end(), ' '), line.end());
         delim_pos = line.find('=');
diff --git a/io.h b/io.h
index 9837d04..ec4f620 100644
--- a/io.h
+++ b/io.h
@@ -5,9 +5,10 @@
 #include <unordered_map>
 #include <map>
 #include <string>
+#include <filesystem>
 #include <vector>
 
-std::unordered_map<std::string, double> parse_arguments(const char *);
+std::unordered_map<std::string, double> parse_arguments(const std::filesystem::path&);
 
 void fid_write_out(const std::string&, const std::vector<double>&, const std::vector<double>&, double, double);
 void fid_write_out(const std::string&, const std::vector<double>&, const std::map<double, std::vector<double>>&, double tau);
diff --git a/main.cpp b/main.cpp
index d73cfcf..98a94e5 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,3 +1,4 @@
+#include <iostream>
 #include <unordered_map>
 #include <random>
 
@@ -7,8 +8,15 @@
 #include "times/delta.h"
 
 
-int main () {
-    std::unordered_map parameter { parse_arguments("config.txt") };
+int main (int argc, char *argv[]) {
+
+    if (argc < 2) {
+        std::cerr << "Usage: " << argv[0] << " PARAMETER_FILE" << std::endl;
+        return 1;
+    }
+    std::cout << argv[0] << std::endl;
+
+    std::unordered_map parameter { parse_arguments(argv[1]) };
 
     std::random_device rd;
     std::mt19937_64 rng(rd());
diff --git a/motions/base.cpp b/motions/base.cpp
index f05d017..457cc24 100644
--- a/motions/base.cpp
+++ b/motions/base.cpp
@@ -2,11 +2,14 @@
 // Created by dominik on 8/12/24.
 //
 
-#include <cmath>
+// #include <cmath>
 #include <random>
+#include <cmath>
+#include <utility>
 
 #include "base.h"
 
+
 Motion::Motion(const double delta, const double eta, std::mt19937_64& rng) : m_delta(delta), m_eta(eta), m_rng(rng) {
     m_uni_dist = std::uniform_real_distribution(0., 1.);
 }
@@ -19,13 +22,13 @@ double Motion::omega_q(const double cos_theta, const double phi) const {
     const double cos_theta_square = cos_theta * cos_theta;
     const double sin_theta_square = 1. - cos_theta_square;
 
-    return M_PI * m_delta * (3 * cos_theta_square - 1 - m_eta * sin_theta_square * cos(2.*phi));
+    return M_PI * m_delta * (3 * cos_theta_square - 1 - m_eta * sin_theta_square * std::cos(2.*phi));
 }
 
-double Motion::draw_position() {
+std::pair<double, double> Motion::draw_position() {
     const double cos_theta = 1 - 2 * m_uni_dist(m_rng);
     const double phi = 2.0 * M_PI * m_uni_dist(m_rng);
 
-    return omega_q(cos_theta, phi);
+    return std::make_pair(cos_theta, phi);
 }
 
diff --git a/motions/base.h b/motions/base.h
index 06442e4..6cceb51 100644
--- a/motions/base.h
+++ b/motions/base.h
@@ -7,6 +7,7 @@
 
 
 #include <random>
+#include <utility>
 
 class Motion {
 public:
@@ -15,9 +16,10 @@ public:
     Motion(double, double, std::mt19937_64&);
     explicit Motion(std::mt19937_64&);
 
-    double draw_position();
+    std::pair<double, double> draw_position();
     [[nodiscard]] double omega_q(double, double) const;
 
+    virtual void initialize() = 0;
     virtual double jump() = 0;
 
     [[nodiscard]] double getDelta() const { return m_delta; }
@@ -25,11 +27,11 @@ public:
     [[nodiscard]] double getEta() const { return m_eta; }
     void setEta(const double eta) { m_eta = eta; }
 
-private:
+protected:
     double m_delta{1.};
     double m_eta{0.};
     std::mt19937_64& m_rng;
-    std::uniform_real_distribution<double> m_uni_dist;
+    std::uniform_real_distribution<> m_uni_dist;
 };
 
 #endif //RWSIM_MOTIONBASE_H
diff --git a/motions/random.cpp b/motions/random.cpp
index d6bc9f1..fe68628 100644
--- a/motions/random.cpp
+++ b/motions/random.cpp
@@ -9,6 +9,9 @@ RandomJump::RandomJump(const double delta, const double eta, std::mt19937_64 &rn
 
 RandomJump::RandomJump(std::mt19937_64 &rng) : Motion(rng) {}
 
+void RandomJump::initialize() {}
+
 double RandomJump::jump() {
-    return draw_position();
+    const auto [cos_theta, phi] = draw_position();
+    return omega_q(cos_theta, phi);
 }
diff --git a/motions/random.h b/motions/random.h
index 0645583..ed4f9e2 100644
--- a/motions/random.h
+++ b/motions/random.h
@@ -13,6 +13,7 @@ public:
     RandomJump(double, double, std::mt19937_64&);
     explicit RandomJump(std::mt19937_64&);
 
+    void initialize() override;
     double jump() override;
 };
 
diff --git a/motions/tetrahedral.cpp b/motions/tetrahedral.cpp
index e5991b3..c9eb2ee 100644
--- a/motions/tetrahedral.cpp
+++ b/motions/tetrahedral.cpp
@@ -9,6 +9,46 @@ TetrahedralJump::TetrahedralJump(const double delta, const double eta, std::mt19
 
 TetrahedralJump::TetrahedralJump(std::mt19937_64& rng) : Motion(rng) {}
 
-double TetrahedralJump::jump() {
-    return draw_position();
+void TetrahedralJump::initialize() {
+    // const auto [cos_theta, phi] = draw_position();
+    //
+    // m_corners[0] = omega_q(cos_theta, phi);
+    //
+    // const double alpha = 2. * M_PI * m_uni_dist(m_rng);
+    // std::cout << alpha << std::endl;
+
+    // v1[0] = sin(phi0)*sin(teta0);
+    // v2[0] = cos(phi0)*sin(teta0);
+    // v3[0] = cos(teta0);
+    //
+    // abs = v1[0]*v1[0]+v2[0]*v2[0]+v3[0]*v3[0];  // Normalization
+    // v1[0] = v1[0]/abs;
+    // v2[0] = v2[0]/abs;
+    // v3[0] = v3[0]/abs;
+    //
+    // /*Calculating the components of the other orientationts. Compare Master Thesis M. Sattig,corrected Version (Share/Abschlussarbeiten)*/
+    //     norm = sqrt(1 - v3[0]*v3[0])+1E-12;
+    //     normI = 1.0/(norm);
+    //
+    //     cosgama = cos(delta0);
+    //     singama = sin(delta0);
+    //     v1[1] = v1[0]*cosBETA + sinBETA*normI*(-v1[0]*v3[0]*singama - v2[0]*cosgama);
+    //     v2[1] = v2[0]*cosBETA + sinBETA*normI*(-v2[0]*v3[0]*singama + v1[0]*cosgama);
+    //     v3[1] = v3[0]*cosBETA + sinBETA*norm*singama;
+    //
+    //     cosgama = cos(gama + delta0);
+    //     singama = sin(gama + delta0);
+    //     v1[2] = v1[0]*cosBETA + sinBETA*normI*(-v1[0]*v3[0]*singama - v2[0]*cosgama);
+    //     v2[2] = v2[0]*cosBETA + sinBETA*normI*(-v2[0]*v3[0]*singama + v1[0]*cosgama);
+    //     v3[2] = v3[0]*cosBETA + sinBETA*norm*singama;
+    //
+    //     cosgama = cos(2.0*gama + delta0);
+    //     singama = sin(2.0*gama + delta0);
+    //     v1[3] = v1[0]*cosBETA + sinBETA*normI*(-v1[0]*v3[0]*singama - v2[0]*cosgama);
+    //     v2[3] = v2[0]*cosBETA + sinBETA*normI*(-v2[0]*v3[0]*singama + v1[0]*cosgama);
+    //     v3[3] = v3[0]*cosBETA + sinBETA*norm*singama;
+}
+
+double TetrahedralJump::jump() {
+    return 0.;
 }
diff --git a/motions/tetrahedral.h b/motions/tetrahedral.h
index 04315ab..78cba62 100644
--- a/motions/tetrahedral.h
+++ b/motions/tetrahedral.h
@@ -7,13 +7,20 @@
 
 #include "base.h"
 #include <random>
+#include <cmath>
+#include <array>
 
 class TetrahedralJump final : public Motion {
 public:
     TetrahedralJump(double, double, std::mt19937_64&);
     explicit TetrahedralJump(std::mt19937_64&);
 
+    void initialize() override;
     double jump() override;
+
+private:
+    const double m_beta{std::acos(-1/3.)};
+    std::array<double, 4> m_corners{};
 };
 
 
diff --git a/ranges.cpp b/ranges.cpp
index 0fdff2e..d10faac 100644
--- a/ranges.cpp
+++ b/ranges.cpp
@@ -49,8 +49,8 @@ std::vector<double> logspace(const double start, const double stop, const int st
         return range;
     }
 
-    const double logstart = log10(start);
-    const double logstop = log10(stop);
+    const double logstart = std::log10(start);
+    const double logstop = std::log10(stop);
 
     const double stepsize = (logstop-logstart) / (steps-1);
     for (int i=0; i<steps; i++) {
diff --git a/sims.cpp b/sims.cpp
index 65cbf78..c4196ec 100644
--- a/sims.cpp
+++ b/sims.cpp
@@ -73,7 +73,7 @@ void run_spectrum(std::unordered_map<std::string, double>& parameter, Motion& mo
                     current_pos = nearest_index(traj_time, real_time, current_pos);
                     const double phase_acq = lerp(traj_time, traj_phase, real_time, current_pos);
 
-                    fid_j[acq_idx] += cos(phase_acq - 2 * phase_tevo) / num_walker;
+                    fid_j[acq_idx] += std::cos(phase_acq - 2 * phase_tevo) / num_walker;
                 }
                 last_print_out = printSteps(last_print_out, start, num_walker, mol_i);
             }
@@ -95,7 +95,8 @@ void run_ste(std::unordered_map<std::string, double>& parameter, Motion& motion,
     const int num_acq = static_cast<int>(parameter[std::string("num_acq")]);
     const int num_walker = static_cast<int>(parameter[std::string("num_walker")]);
 
-    const std::vector<double> correlation_times = logspace(parameter["tau_start"], parameter["tau_stop"], static_cast<int>(parameter["tau_steps"]));
+    const double tau = parameter["tau"];
+    dist.setTau(tau);
 
     motion.setDelta(parameter["delta"]);
     motion.setEta(parameter["eta"]);
@@ -103,7 +104,6 @@ void run_ste(std::unordered_map<std::string, double>& parameter, Motion& motion,
     const std::vector<double> evolution_times = linspace(parameter["tevo_start"], parameter["tevo_stop"], static_cast<int>(parameter["tevo_steps"]));
     const std::vector<double> mixing_times = linspace(parameter["tevo_start"], parameter["tevo_stop"], static_cast<int>(parameter["tevo_steps"]));
 
-
     std::map<double, std::vector<double>> fid_dict;
     for (auto t_evo_i: evolution_times) {
         fid_dict[t_evo_i] = std::vector<double>(num_acq);
@@ -111,54 +111,50 @@ void run_ste(std::unordered_map<std::string, double>& parameter, Motion& motion,
     }
 
     // each trajectory must have a duration of at least tmax
-
     const double tmax = *std::max_element(evolution_times.begin(), evolution_times.end()) * 2 + *std::max_element(mixing_times.begin(), mixing_times.end());
 
-    for (const auto tau_i: correlation_times) {
-        auto start = std::chrono::system_clock::now();
-        time_t start_time = std::chrono::system_clock::to_time_t(start);
-        std::cout << "Start tau = " <<  tau_i << "s : " << ctime(&start_time);
+    const auto start = std::chrono::system_clock::now();
+    const time_t start_time = std::chrono::system_clock::to_time_t(start);
+    std::cout << "Start tau = " << tau << "s : " << ctime(&start_time);
 
-        dist.setTau(tau_i);
+    for (auto& [_, fid_j]: fid_dict) {
+        std::fill(fid_j.begin(), fid_j.end(), 0.);
+    }
 
-        for (auto& [_, fid_j]: fid_dict) {
-            std::fill(fid_j.begin(), fid_j.end(), 0.);
-        }
+    // reset array for each correlation time
+    for (int mol_i = 0; mol_i < num_walker; mol_i++){
+        std::vector<double> traj_time{};
+        std::vector<double> traj_phase{};
 
-        // reset array for each correlation time
-        for (int mol_i = 0; mol_i < num_walker; mol_i++){
-            std::vector<double> traj_time{};
-            std::vector<double> traj_phase{};
+        make_trajectory(motion, dist, tmax, traj_time, traj_phase);
 
-            make_trajectory(motion, dist, tmax, traj_time, traj_phase);
+        for (auto& [t_evo_j, fid_j] : fid_dict) {
+            int current_pos = nearest_index(traj_time, t_evo_j, 0);
+            const double phase_tevo = lerp(traj_time, traj_phase, t_evo_j, current_pos);
 
-            for (auto& [t_evo_j, fid_j] : fid_dict) {
-                int current_pos = nearest_index(traj_time, t_evo_j, 0);
-                const double phase_tevo = lerp(traj_time, traj_phase, t_evo_j, current_pos);
+            // time axis by echo delay to get time in trajectory
 
-                // time axis by echo delay to get time in trajectory
+            for (int acq_idx = 0; acq_idx < num_acq; acq_idx++) {
+                const double real_time = mixing_times[acq_idx] + t_evo_j;
 
-                for (int acq_idx = 0; acq_idx < num_acq; acq_idx++) {
-                    const double real_time = mixing_times[acq_idx] + t_evo_j;
+                current_pos = nearest_index(traj_time, real_time, current_pos);
+                const double phase_acq = lerp(traj_time, traj_phase, real_time, current_pos);
 
-                    current_pos = nearest_index(traj_time, real_time, current_pos);
-                    const double phase_acq = lerp(traj_time, traj_phase, real_time, current_pos);
-
-                    fid_j[acq_idx] += cos(phase_acq - 2 * phase_tevo);
-                }
+                fid_j[acq_idx] += cos(phase_acq - 2 * phase_tevo);
             }
         }
-
-        // write fid to files
-        fid_write_out("ste", mixing_times, fid_dict, tau_i);
-
-        auto end = std::chrono::system_clock::now();
-
-        std::chrono::duration<float> duration = end - start;
-        time_t end_time = std::chrono::system_clock::to_time_t(end);
-        std::cout << "End   tau = " << tau_i << "s : " << ctime(&end_time);
-        std::cout << "Duration: " << duration.count() << "s\n" << std::endl;
     }
+
+    // write fid to files
+    fid_write_out("ste", mixing_times, fid_dict, tau);
+
+    const auto end = std::chrono::system_clock::now();
+
+    const std::chrono::duration<float> duration = end - start;
+    const time_t end_time = std::chrono::system_clock::to_time_t(end);
+    std::cout << "End   tau = " << tau << "s : " << ctime(&end_time);
+    std::cout << "Duration: " << duration.count() << "s\n" << std::endl;
+
 }
 
 
@@ -167,6 +163,8 @@ void make_trajectory(Motion& motion, const Distribution& dist, const double t_ma
     double t_passed = 0;
     double phase = 0;
 
+    motion.initialize();
+
     out_time.emplace_back(t_passed);
     out_phase.emplace_back(0);
 
@@ -176,8 +174,6 @@ void make_trajectory(Motion& motion, const Distribution& dist, const double t_ma
 
         phase += motion.jump() * t;
 
-//        phase += jump(delta, eta, rng) * t;
-
         out_time.emplace_back(t_passed);
         out_phase.emplace_back(phase);
     }