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vatman

Untitled

May 8th, 2024
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C++ 1.62 KB | None | 0 0
  1. #include <cmath>
  2. #include <iostream>
  3.  
  4. void method_vr() {
  5.   double w = 1.2; // 0<w<2
  6.   int N_max = 10000;
  7.   int S = 0;
  8.   double eps = 0.0001;
  9.   double eps_max = 0;
  10.   double eps_cur = 0;
  11.   int n;
  12.   std::cout << "input n" << '\n';
  13.   std::cin >> n;
  14.   double a[n][n];
  15.   double x[n];
  16.   double b[n];
  17.   std::cout << "input a[n][n]" << '\n';
  18.   for (int i = 0; i < n; ++i) {
  19.     for (int j = 0; j < n; ++j) {
  20.       std::cin >> a[i][j];
  21.     }
  22.   }
  23.   std::cout << "input b[n]" << '\n';
  24.   for (int j = 0; j < n; ++j) {
  25.     std::cin >> b[j];
  26.   }
  27.   std::cout << "input x[n]" << '\n';
  28.   for (int j = 0; j < n; ++j) {
  29.     std::cin >> x[j];
  30.   }
  31.   for (int i = 0; i < n; ++i) {
  32.     for (int j = 0; j < n; ++j) {
  33.       std::cout << a[i][j] << ' ';
  34.     }
  35.     std::cout << b[i] << '\n';
  36.   }
  37.  
  38.   double x_old;
  39.   double x_new;
  40.   bool f = false;
  41.   while (!f) {
  42.     for (int i = 0; i < n; ++i) {
  43.       x_old = x[i];
  44.       x_new = (1 - w) * a[i][i] * x[i] + w * b[i];
  45.       for (int j = 0; j < n; ++j) {
  46.         if (j != i) {
  47.           x_new -= w * a[i][j] * x[j];
  48.         }
  49.       }
  50.       x_new /= a[i][i];
  51.       eps_cur = fabs(x_old - x_new);
  52.       if (i == 1) {
  53.         eps_max = eps_cur;
  54.       } else if (eps_cur > eps_max) {
  55.         eps_max = eps_cur;
  56.       }
  57.       x[i] = x_new;
  58.     }
  59.     S += 1;
  60.     if ((eps_max <= eps) || (S >= N_max)) {
  61.       f = true;
  62.       std::cout << "eps_max: " << eps_max << '\n';
  63.     }
  64.   }
  65.   for (int i = 0; i < n; ++i) {
  66.     std::cout << S << ':' << x[i] << ' ';
  67.   }
  68.   std::cout << '\n';
  69.   std::cout << "count of steps: " << S << '\n';
  70. }
  71.  
  72. int main() {
  73.   method_vr();
  74.   return 0;
  75. }
  76.  
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