cross testing FTCS prototype with existing ADI solution

examples/second_example.cpp

@@ -2,6 +2,8 @@
 #include <tug/Diffusion.hpp>
 
 #include <iostream>
+#include <fstream>
+#include <string>
 
 using namespace std;
 using namespace tug::diffusion;
@@ -10,12 +12,12 @@ using namespace tug::bc;
 int main(int argc, char *argv[]) {
 
     int dim = 2;
-    int n = 5;
-    int m = 5;
+    int n = 20;
+    int m = 20;
 
-    vector<double> alpha(n * m, 1e-1);
+    vector<double> alpha(n * m, 1);
     vector<double> field(n * m, 0);
-    field[0] = 1e-6;
+    field[0] = 2000;
     // for (int i = 1; i<20; i++) {
     //     for (int j = 0; j<20; j++ ) {
     //         field[i] = 0;
@@ -33,25 +35,55 @@ int main(int argc, char *argv[]) {
     cout << endl;
 
     TugInput input_param;
-    input_param.setTimestep(1.);
+    input_param.setTimestep(0.1);
     input_param.setGridCellN(n, m);
     input_param.setDomainSize(n, m);
     BoundaryCondition bc(n, m);
+    boundary_condition bc_constant;
+    bc_constant.type = BC_TYPE_CONSTANT;
+    bc_constant.value = 0;
+    bc.setSide(BC_SIDE_LEFT, bc_constant);
+    bc.setSide(BC_SIDE_TOP, bc_constant);
+    bc.setSide(BC_SIDE_RIGHT, bc_constant);
+    bc.setSide(BC_SIDE_BOTTOM, bc_constant);
     input_param.setBoundaryCondition(bc);
 
+    // int iterations = 1000;
+    // for (int t = 0; t < iterations; t++) {
+    //     double result = ADI_2D(input_param, &field[0], &alpha[0]);
+
+    //     if (t % 100 == 0) {
+    //         cout << "Iteration " << t << ":" << endl;
+    //         for (int i = 0; i<n; i++) {
+    //             for (int j = 0; j<m; j++) {
+    //                 cout << field[n * i + j] << " ";
+    //             }
+    //             cout << endl;
+    //         }
+    //         cout << endl;
+    //     }
+    // }
+
+    ofstream myfile;
+    myfile.open("output.csv"); 
+    if (!myfile) {
+        exit(1);
+    }
+
     int iterations = 1000;
     for (int t = 0; t < iterations; t++) {
         double result = ADI_2D(input_param, &field[0], &alpha[0]);
-
-        if (t % 100 == 0) {
-            cout << "Iteration " << t << ":" << endl;
-            for (int i = 0; i<n; i++) {
-                for (int j = 0; j<m; j++) {
-                    cout << field[n * i + j] << " ";
+    
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                myfile << field[i * m + j];
+                if (j < m-1) {
+                    myfile << ", ";
                 }
-                cout << endl;
             }
-            cout << endl;
+            myfile << "\n";
         }
+        myfile << std::endl << std::endl;
     }
+    myfile.close();
 }