Adding timer to simulate

app/main_2D_mdl.cpp

@@ -53,7 +53,10 @@ int main(int argc, char *argv[]) {
 
   // Now we simulate and output 8 steps à 1 sec
   for (int t = 1; t < 6; t++) {
-    diffu.simulate(field.data(), alpha.data(), bc.data());
+    double time = diffu.simulate(field.data(), alpha.data(), bc.data());
+
+    cerr << "time elapsed: " << time << " seconds" << endl;
+
     cout << t;
     
     for (int i=0; i < m*n; i++) {

src/BTCSDiffusion.cpp

@@ -8,6 +8,7 @@
 #include <algorithm>
 #include <array>
 #include <cassert>
+#include <chrono>
 #include <cstddef>
 #include <iomanip>
 #include <iterator>
@@ -286,8 +287,13 @@ void Diffusion::BTCSDiffusion::setTimestep(double time_step) {
   this->time_step = time_step;
 }
 
-void Diffusion::BTCSDiffusion::simulate(double *c, double *alpha,
+auto Diffusion::BTCSDiffusion::simulate(double *c, double *alpha,
-                                        Diffusion::boundary_condition *bc) {
+                                        Diffusion::boundary_condition *bc)
+    -> double {
+
+  std::chrono::high_resolution_clock::time_point start =
+      std::chrono::high_resolution_clock::now();
+
   if (this->grid_dim == 1) {
     Eigen::Map<DVectorRowMajor> c_in(c, this->grid_cells[0]);
     Eigen::Map<const DVectorRowMajor> alpha_in(alpha, this->grid_cells[0]);
@@ -307,6 +313,14 @@ void Diffusion::BTCSDiffusion::simulate(double *c, double *alpha,
 
     simulate2D(c_in, alpha_in, bc_in);
   }
+
+  std::chrono::high_resolution_clock::time_point end =
+      std::chrono::high_resolution_clock::now();
+
+  std::chrono::duration<double> duration =
+      std::chrono::duration_cast<std::chrono::duration<double>>(end - start);
+
+  return duration.count();
 }
 
 inline auto Diffusion::BTCSDiffusion::getBCFromFlux(boundary_condition bc,

src/BTCSDiffusion.hpp

@@ -88,11 +88,16 @@ public:
   /*!
    * With given ghost zones simulate diffusion. Only 1D allowed at this moment.
    *
-   * @param c Pointer to continious memory describing the current concentration state of each grid cell.
+   * @param c Pointer to continious memory describing the current concentration
-   * @param alpha Pointer to memory area of diffusion coefficients for each grid element.
+   * state of each grid cell.
+   * @param alpha Pointer to memory area of diffusion coefficients for each grid
+   * element.
    * @param bc Pointer to memory setting boundary conidition of each grid cell.
+   *
+   * @return Time in seconds [s] used to simulate one iteration.
    */
-  void simulate(double *c, double *alpha, Diffusion::boundary_condition *bc);
+  auto simulate(double *c, double *alpha, Diffusion::boundary_condition *bc)
+      -> double;
 
   /*!
    * Set the timestep of the simulation