diff --git a/include/diffusion/BTCSDiffusion.hpp b/include/diffusion/BTCSDiffusion.hpp
index ef4c4d6..e9eb868 100644
--- a/include/diffusion/BTCSDiffusion.hpp
+++ b/include/diffusion/BTCSDiffusion.hpp
@@ -135,16 +135,17 @@ private:
                  const BCMatrixRowMajor &bc, double time_step, double dx)
       -> DMatrixRowMajor;
 
-  void fillMatrixFromRow(Eigen::SparseMatrix<double> &A_matrix,
-                         const DVectorRowMajor &alpha,
-                         const BCVectorRowMajor &bc, int size, double dx,
-                         double time_step);
+  static void fillMatrixFromRow(Eigen::SparseMatrix<double> &A_matrix,
+                                const DVectorRowMajor &alpha,
+                                const BCVectorRowMajor &bc, int size, double dx,
+                                double time_step);
 
-  void fillVectorFromRow(Eigen::VectorXd &b_vector, const DVectorRowMajor &c,
-                         const DVectorRowMajor &alpha,
-                         const BCVectorRowMajor &bc,
-                         const DVectorRowMajor &t0_c, int size, double dx,
-                         double time_step);
+  static void fillVectorFromRow(Eigen::VectorXd &b_vector,
+                                const DVectorRowMajor &c,
+                                const DVectorRowMajor &alpha,
+                                const BCVectorRowMajor &bc,
+                                const DVectorRowMajor &t0_c, int size,
+                                double dx, double time_step);
   void simulate3D(std::vector<double> &c);
 
   inline static auto getBCFromFlux(Diffusion::boundary_condition bc,
diff --git a/src/BTCSDiffusion.cpp b/src/BTCSDiffusion.cpp
index 54b9789..240d76a 100644
--- a/src/BTCSDiffusion.cpp
+++ b/src/BTCSDiffusion.cpp
@@ -179,14 +179,15 @@ auto Diffusion::BTCSDiffusion::calc_t0_c(const DMatrixRowMajor &c,
 
   DMatrixRowMajor t0_c(n_rows, n_cols);
 
-  std::array<double, 3> y_values;
+  std::array<double, 3> y_values{};
 
   // first, iterate over first row
   for (int j = 0; j < n_cols; j++) {
     boundary_condition tmp_bc = bc(0, j + 1);
 
-    if (tmp_bc.type == Diffusion::BC_CLOSED)
+    if (tmp_bc.type == Diffusion::BC_CLOSED){
       continue;
+    }
 
     y_values[0] = getBCFromFlux(tmp_bc, c(0, j), alpha(0, j));
     y_values[1] = c(0, j);
@@ -216,8 +217,9 @@ auto Diffusion::BTCSDiffusion::calc_t0_c(const DMatrixRowMajor &c,
   for (int j = 0; j < n_cols; j++) {
     boundary_condition tmp_bc = bc(end + 1, j + 1);
 
-    if (tmp_bc.type == Diffusion::BC_CLOSED)
+    if (tmp_bc.type == Diffusion::BC_CLOSED) {
       continue;
+    }
 
     y_values[0] = c(end - 1, j);
     y_values[1] = c(end, j);