diff --git a/src/run.cpp b/src/run.cpp
index 9bf4158..e336284 100644
--- a/src/run.cpp
+++ b/src/run.cpp
@@ -20,6 +20,21 @@ using TugType = double;
 using RowMajorMat =
     Eigen::Matrix<TugType, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>;
 
+static inline std::vector<TugType>
+eigenMatrix_to_vector(const Eigen::MatrixX<TugType> &mat) {
+  if (mat.IsRowMajor) {
+    return std::vector<TugType>(mat.data(), mat.data() + mat.size());
+  } else {
+    std::vector<TugType> out_vec(mat.size());
+    for (int i = 0; i < mat.rows(); i++) {
+      for (int j = 0; j < mat.cols(); j++) {
+        out_vec[i * mat.cols() + j] = mat(i, j);
+      }
+    }
+    return out_vec;
+  }
+}
+
 double run_bench(const bench_input &input, const std::string &output_file) {
   std::vector<std::vector<double>> raw_data =
       read_conc_csv<double>(input.csv_file, input.ncols, input.nrows);
@@ -77,8 +92,7 @@ double run_bench(const bench_input &input, const std::string &output_file) {
 
     const auto &result = grid.getConcentrations();
 
-    raw_data[i] =
-        std::vector<TugType>(result.data(), result.data() + result.size());
+    raw_data[i] = eigenMatrix_to_vector(result);
   }
 
   const auto end_t = std::chrono::high_resolution_clock::now();