Some stuff

latex/problems/problem7.tex

@@ -1,3 +1,9 @@
 \section*{Problem 7}
 
+\subsection*{a)}
 % Link to relevant files on gh and possibly add some comments
+The code can be found at https://github.uio.no/FYS3150-G2-2023/Project-1/blob/coryab/final-run/src/generalAlgorithm.cpp
+
+\subsection*{b)}
+
+\includegraphics{problem7}

src/funcs.cpp

@@ -4,6 +4,10 @@ double f(double x) {
     return 100*std::exp(-10*x);
 }
 
+double u(double x) {
+    return 1. - (1. - std::exp(-10.))*x - std::exp(-10.*x);
+}
+
 void build_g_vec(int n_steps, arma::vec& g_vec) {
     g_vec.resize(n_steps-1);
 

src/funcs.hpp

@@ -4,10 +4,12 @@
 #include <armadillo>
 #include <cmath>
 
-#define PRECISION 8
+#define PRECISION 20
 
 double f(double x);
 
+double u(double x);
+
 void build_g_vec(int n_steps, arma::vec& g_vec);
 
 void build_arrays(

src/generalAlgorithm.cpp

@@ -58,7 +58,7 @@ void general_algorithm_error()
     int steps;
     double step_size, abs_err, rel_err, u_i, v_i;
 
-    for (int i=0; i < 6; i++) {
+    for (int i=0; i < 7; i++) {
         steps = std::pow(10, i+1);
         step_size = 1./(double) steps;
 
@@ -69,16 +69,16 @@ void general_algorithm_error()
         ofile.open("output/error/out_" + std::to_string(steps) + ".txt");
 
         for (int j=0; j < v_vec.n_elem; j++) {
-            u_i = f(step_size*(j+1));
+            u_i = u(step_size*(j+1));
             v_i = v_vec(j);
+            abs_err = u_i - v_i;
             ofile << std::setprecision(PRECISION) << std::scientific 
                 << step_size*(j+1) << ","
                 << std::setprecision(PRECISION) << std::scientific 
-                << std::log10(std::abs(u_i - v_i)) << ","
+                << std::log10(std::abs(abs_err)) << ","
                 << std::setprecision(PRECISION) << std::scientific 
-                << std::log10(std::abs((u_i - v_i)/u_i)) << std::endl;
+                << std::log10(std::abs(abs_err/u_i)) << std::endl;
         }
         ofile.close();
-        
     }
 }

src/plot_general_alg.py

@@ -4,12 +4,12 @@ import numpy as np
 analytical_func = lambda x: 1 - (1 - np.exp(-10))*x - np.exp(-10*x)
 
 def main():
-    for i in range(2):
+    for i in range(6):
         x = []
         y = []
         x.append(0.)
         y.append(0.)
-        with open(f"output/problem7/out_{10**(i+1)}.txt", "r") as f:
+        with open(f"output/general/out_{10**(i+1)}.txt", "r") as f:
             lines = f.readlines()
             for line in lines:
                 x_i, y_i = line.strip().split(",")

src/plot_general_alg_error.py

@@ -1,7 +1,7 @@
 import matplotlib.pyplot as plt
 
 def main():
-    _, axs = plt.subplots(2)
+    fig, axs = plt.subplots(1)
     for i in range(6):
         x = []
         abs_err = []
@@ -16,10 +16,14 @@ def main():
 
         axs[0].plot(x, abs_err, label=f"abs_err {10**(i+1)} steps")
         axs[1].plot(x, rel_err, label=f"rel_err {10**(i+1)} steps")
+        print(max(rel_err))
+        axs[2].plot(i+1, max(rel_err), marker="o", markersize=10)
 
     axs[0].legend(bbox_to_anchor=(1.05, 1), loc=2, borderaxespad=0.)
     axs[1].legend(bbox_to_anchor=(1.05, 1), loc=2, borderaxespad=0.)
     plt.savefig("../latex/images/problem8.pdf", bbox_inches="tight")
+    fig.2
+    
 
 if __name__ == "__main__":
     main()