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  1. #include <iostream>
  2. #include <iomanip>
  3. #include <cmath>
  4. #include <chrono>
  5.  
  6. class muTimer
  7. {
  8.     using Clock = std::chrono::high_resolution_clock;
  9.     bool active = false;
  10.     Clock::duration   duration_;
  11.     Clock::time_point start_ = Clock::now(), stop_ = Clock::now();
  12.  
  13.     muTimer(const muTimer&)             = delete;
  14.     muTimer& operator=(const muTimer&)  = delete;
  15. public:
  16.     using ns       = std::chrono::nanoseconds;
  17.     using mks      = std::chrono::microseconds;
  18.     using ms       = std::chrono::milliseconds;
  19.     muTimer() { reset(); start(); }
  20.     ~muTimer() = default;
  21.     muTimer& reset()
  22.     {
  23.         duration_ = std::chrono::nanoseconds(0);
  24.         active    = false;
  25.         return *this;
  26.     }
  27.     muTimer& start()
  28.     {
  29.         if (!active)
  30.         {
  31.             start_ = Clock::now();
  32.             active = true;
  33.         }
  34.         return *this;
  35.     }
  36.     muTimer& stop()
  37.     {
  38.         if (active)
  39.         {
  40.             stop_      = Clock::now();
  41.             duration_ += stop_ - start_;
  42.             active     = false;
  43.         }
  44.         return *this;
  45.     }
  46.     template<typename T = mks>
  47.         unsigned long long duration()
  48.     {
  49.         return static_cast<unsigned long long>
  50.             (std::chrono::duration_cast<T>(stop_-start_).count());
  51.     }
  52. };
  53.  
  54.  
  55. using namespace std;
  56.  
  57. double pi = 3.14159265358;
  58.  
  59. double Paul(double x, double eps)
  60. {
  61.     double y = 1, summa = 0, last = 1;;
  62.     for (; fabs(last) > eps;)
  63.     {
  64.         last = pow(-1, y) * pow(x, 2 * y - 1) / (2 * y - 1);
  65.         summa += last;
  66.         y+=1;
  67.     }
  68.     return pi/2 + summa;
  69. }
  70.  
  71. double Harry(double x, double eps)
  72. {
  73.     double summ = pi/2 - x, x2n_1 = -x;
  74.     x *= x;
  75.  
  76.     for(int k = 3; fabs(x2n_1/k) > eps; k += 2)
  77.     {
  78.         x2n_1 *= -x;
  79.         summ += x2n_1/k;
  80.     }
  81.     return summ;
  82. }
  83.  
  84. int main()
  85. {
  86.     {
  87.         muTimer mt;
  88.         double z = 0;
  89.         for(double x = 0; x < 0.95; x += 0.000001)
  90.             z += Paul(x,1e-10);
  91.         mt.stop();
  92.         cout << z << " for " << mt.duration<>() << " mks\n";
  93.     }
  94.     {
  95.         muTimer mt;
  96.         double z = 0;
  97.         for(double x = 0; x < 0.95; x += 0.000001)
  98.             z += Harry(x,1e-10);
  99.         mt.stop();
  100.         cout << z << " for " << mt.duration<>() << " mks\n";
  101.     }
  102. }
  103.  
Success #stdin #stdout 1.69s 4180KB
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stdin
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Standard input is empty
stdout
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1.09207e+06 for 1496617 mks
1.09207e+06 for 192588 mks
https://ideone.com/NuGWhW
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
public

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