Finish special algo and add write to file and plot

src/main.cpp

@@ -0,0 +1,24 @@
+#include "GeneralAlgorithm.hpp"
+#include <armadillo>
+#include <iostream>
+
+double f(double x) {
+    return 100. * std::exp(-10.*x);
+}
+
+double a_sol(double x) {
+    return 1. - (1. - std::exp(-10)) * x - std::exp(-10*x);
+}
+
+int main() {
+    arma::mat A = arma::eye(3,3);
+
+    GeneralAlgorithm ga(3, &A, f, a_sol, 0., 1.);
+
+    ga.solve();
+    std::cout << "Time: " << ga.time(5) << std::endl;
+    ga.error();
+
+    return 0;
+
+}

src/simpleFile.cpp

@@ -1,4 +1,12 @@
 #include <armadillo>
+#include <cmath>
+#include <ctime>
+#include <fstream>
+#include <iomanip>
+#include <ios>
+#include <string>
+
+#define TIMING_ITERATIONS 5
 
 arma::vec* general_algorithm(
     arma::vec* sub_diag,
@@ -50,26 +58,105 @@ arma::vec* special_algorithm(
     return g_vec;
 }
 
-arma::vec* error(
+void error(
+    std::string filename,
+    arma::vec* x_vec,
     arma::vec* v_vec,
     arma::vec* a_vec
 )
 {
+    std::ofstream ofile;
+    ofile.open(filename);
 
-}
-
-double time() {
-
-}
-
-int main() {
-    int n = 10;
-    arma::vec x = arma::vec(n);
-    arma::vec y = arma::vec(n);
-    double step_size = 1.0 / n;
-
-    for (int i = 0; i < n; i++) {
-        x(i) = (i+1) * step_size;
-        y(i) = 1.0 - (1.0 - exp(-10))*x(i) - exp(-10*x(i));
+    if (!ofile.is_open()) {
+        exit(1);
     }
+
+    for (int i=0; i < a_vec->n_elem; i++) {
+        double sub = (*a_vec)(i) - (*v_vec)(i);
+        ofile << std::setprecision(8) << std::scientific << (*x_vec)(i)
+            << std::setprecision(8) << std::scientific << std::log10(std::abs(sub))
+            << std::setprecision(8) << std::scientific << std::log10(std::abs(sub/(*a_vec)(i)))
+            << std::endl;
+    }
+    
+    ofile.close();
+
+}
+
+double f(double x) {
+    return 100*std::exp(-10*x);
+}
+
+void build_array(
+    int n_steps, 
+    arma::vec* sub_diag, 
+    arma::vec* main_diag, 
+    arma::vec* sup_diag,
+    arma::vec* g_vec
+) 
+{
+    sub_diag->resize(n_steps-2);
+    main_diag->resize(n_steps-1);
+    sup_diag->resize(n_steps-2);
+
+    sub_diag->fill(-1);
+    main_diag->fill(2);
+    sup_diag->fill(-1);
+
+    g_vec->resize(n_steps-1);
+
+    double step_size = 1./ (double) n_steps;
+    for (int i=0; i < n_steps-1; i++) {
+        (*g_vec)(i) = f((i+1)*step_size);
+    }
+
+}
+
+void timing() {
+    arma::vec sub_diag, main_diag, sup_diag, g_vec;
+    int n_steps;
+
+    std::ofstream ofile;
+    ofile.open("timing.txt");
+
+    // Timing
+    for (int i=1; i <= 8; i++) {
+        n_steps = std::pow(10, i);
+        clock_t g_1, g_2, s_1, s_2;
+        double g_res = 0, s_res = 0;
+      
+        for (int j=0; j < TIMING_ITERATIONS; j++) {
+            build_array(n_steps, &sub_diag, &main_diag, &sup_diag, &g_vec);
+
+            g_1 = clock();
+
+            general_algorithm(&sub_diag, &main_diag, &sup_diag, &g_vec);
+
+            g_2 = clock();
+
+            g_res += (double) (g_2 - g_1) / CLOCKS_PER_SEC;
+            build_array(n_steps, &sub_diag, &main_diag, &sup_diag, &g_vec);
+
+            s_1 = clock();
+
+            special_algorithm(-1., 2., -1., &g_vec);
+
+            s_2 = clock();
+
+            s_res += (double) (s_2 - s_1) / CLOCKS_PER_SEC;
+
+        }
+        ofile 
+            << n_steps << ","
+            << g_res / (double) TIMING_ITERATIONS << ","
+            << s_res / (double) TIMING_ITERATIONS << std::endl;
+    }
+
+    ofile.close();
+}
+
+int main() 
+{
+    timing();
 }