From 24f9f88af51e75d1d934ea8bfa164bb4d6bf4f36 Mon Sep 17 00:00:00 2001
From: Janita Willumsen <j.willu@me.com>
Date: Sat, 23 Sep 2023 15:13:24 +0200
Subject: [PATCH] Finish problem 5 and 6

---
 src/main.cpp | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)

diff --git a/src/main.cpp b/src/main.cpp
index e69de29..3a55c90 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -0,0 +1,127 @@
+/** @file main.cpp
+ *  @brief Main program for Project 2
+ *
+ *  The program performs the Jacobi rotation method. 
+ *  The size of the matrix, and number of transformations
+ *  performed are written to file. 
+ *  Eigenvector correstonding to the 3 smallest eigenvalues 
+ *  for matrices of size 6x6 and 100x100 are written to file.
+ *
+ *  @author Cory Alexander Balaton (coryab)
+ *  @author Janita Ovidie Sandtrøen Willumsen (janitaws)
+ *  @bug No known bugs
+ */
+#include <cassert>
+#include <cmath>
+#include <iostream>
+
+#include "utils.hpp"
+#include "matrix.hpp"
+#include "jacobi.hpp"
+
+
+void write_transformation(int N, bool dense)
+{   
+    std::ofstream ofile;
+
+    ofile.open("../latex/output/transform_dense.csv");
+    ofile << "N,T" << std::endl;
+
+    // Increase size of matrix, start at 5 to avoid logic_error of N=4
+    for (int i = 5; i <= N; i++) {
+        arma::mat A = arma::mat(i, i).randn();
+        A = arma::symmatu(A);
+        arma::vec eigval;
+        arma::mat eigvec;
+
+        int iters;
+        bool converged;
+        
+        jacobi_eigensolver(A, 10e-14, eigval, eigvec, 100000, iters, converged);
+
+        // Write size, number of iterations, and converge status to file
+        ofile << i << "," << iters << std::endl;
+    }
+    ofile.close();
+}
+
+    
+void write_transformation(int N)
+{   
+    std::ofstream ofile;
+
+    double h;
+    double a, d;
+
+    ofile.open("../latex/output/transform_tridiag.csv");
+    ofile << "N,T" << std::endl;
+
+    // Increase size of matrix, start at 5 to avoid logic_error of N=4
+    for (int i = 5; i <= N; i++) {
+        h = 1. / (double) (i+1);
+        a = -1. / (h*h), d = 2. / (h*h);
+
+        arma::mat A = create_symmetric_tridiagonal(i, a, d);
+        arma::vec eigval;
+        arma::mat eigvec;
+
+        int iters;
+        bool converged;
+        
+        jacobi_eigensolver(A, 10e-14, eigval, eigvec, 100000, iters, converged);
+
+        // Write size, number of iterations, and converge status to file
+        ofile << i << "," << iters << std::endl;
+    }
+    ofile.close();
+}
+
+
+void write_eigenvec(int N)
+{
+    double h = 1. / (double) (N+1);
+    double a = -1. / (h*h);
+    double d = 2. / (h*h);
+    double x = 0.;
+
+    arma::mat A = create_symmetric_tridiagonal(N, a, d);
+    arma::vec eigval;
+    arma::mat eigvec;
+
+    int iters;
+    bool converged;
+    
+    jacobi_eigensolver(A, 10e-14, eigval, eigvec, 100000, iters, converged);
+
+    std::ofstream ofile;
+    ofile.open("../latex/output/eigenvector_" + std::to_string(N) + ".csv");
+    ofile << "x,Vector 1,Vector 2,Vector 3" << std::endl;
+
+    ofile << scientific_format(0., 16) << "," 
+            << scientific_format(0., 16) << "," 
+            << scientific_format(0., 16) << "," 
+            << scientific_format(0., 16) << std::endl;
+
+    for (int i = 0; i < N; i++) {
+        x += h;
+        ofile << scientific_format(x, 16)<< "," 
+            << scientific_format(eigvec(i,0), 16) << "," 
+            << scientific_format(eigvec(i,1), 16) << "," 
+            << scientific_format(eigvec(i,2), 16) << std::endl;
+    }
+    ofile << scientific_format(1., 16) << "," 
+            << scientific_format(0., 16) << "," 
+            << scientific_format(0., 16) << "," 
+            << scientific_format(0., 16) << std::endl;
+    ofile.close();
+}
+
+
+int main()
+{
+    write_transformation(100);
+    write_transformation(100, true);
+    write_eigenvec(6);
+    write_eigenvec(100);
+    return 0;
+}