chore: remove unneeded test file

test/simple.cpp

@@ -1,36 +0,0 @@
-#include "grid/BoundaryCondition.hpp"
-#include <Diffusion.hpp>
-#include <iostream>
-#include <vector>
-
-#define SIZE 5
-
-using namespace tug;
-
-int main() {
-  boundary_condition::BoundaryCondition bc(SIZE);
-
-  diffusion::TugDiffuInput in = {1., {SIZE, 0, 0}, {1, 0, 0}, 0};
-
-  std::vector<double> field1(SIZE, 0);
-  std::vector<double> field2(SIZE, 0);
-  std::vector<double> alpha(SIZE, 1e-5);
-
-  bc(boundary_condition::BC_SIDE_LEFT) = {boundary_condition::BC_TYPE_CONSTANT,
-                                          1};
-
-  for (int j = 0; j < 10; j++) {
-    double time1 =
-        diffusion::BTCS_Thomas_1D(field1.data(), alpha.data(), bc, in);
-    double time2 =
-        diffusion::BTCS_EigenLU_1D(field2.data(), alpha.data(), bc, in);
-
-    for (int i = 0; i < SIZE; i++) {
-      std::cout << field1[i] << "\t";
-      std::cout << field2[i] << "\n";
-    }
-
-    std::cout << "Time Thomas = " << time1 << "s \tTime EigenLU = " << time2
-              << " s" << std::endl;
-  }
-}