dft_tools/test/triqs/statistics/observable.cpp

#include <triqs/arrays.hpp>
#include <triqs/statistics.hpp>
#include <iostream>

using triqs::statistics::observable;
using namespace triqs::arrays;

template <typename T>
std::ostream &operator<<(std::ostream &out, std::vector<T> const &v) {
  for (auto const &x : v)
    out << x << " ";
  return out;
}

int main() {

  try {
    {
      auto A = observable<double>{};

      for (int i = 0; i < 1000; ++i)
        A << 6;
      std::cout << average_and_error(A) << std::endl;
    }

    {
      auto A = observable<array<double, 2> >{};

      for (int i = 0; i < 1000; ++i)
        A << array<double, 2>{ { i, 2 * i }, { 3 * i, 4 * i } };

      for (int i = 0; i < 1000; ++i)
        A << 2 * array<double, 2>{ { i, 2 * i }, { 3 * i, 4 * i } };

      std::cout << average(A) << std::endl;
      std::cout << average_and_error(A) << std::endl;
    }

    {
      observable<double> A, B;

      for (int i = 0; i < 1000; ++i) {
        A << i;
        B << 5;
      }

      // operations
      auto ab = A / B;
      //auto ab_j = make_jackknife(A) / make_jackknife(B);
      double r = eval(ab, 1);
      std::cout << "eval A/B in 1 " << r << std::endl;

      r = eval(cos(A), 1);
      std::cout << r << " == " << std::cos(1) << std::endl;

      std::cout << "<A/B> = "<< average(A / B) << std::endl;
      std::cout << average_and_error(A / B) << std::endl;
      std::cout << average_and_error(cos(A)) << std::endl;
      std::cout << average_and_error(cos(A) / B) << std::endl;
    }
  }
  TRIQS_CATCH_AND_ABORT;
}