src/boost/libs/math/example/inverse_gamma_example.cpp


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57

// inverse_gamma_example.cpp

// Copyright Paul A. Bristow 2010.

// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt
// or copy at http://www.boost.org/LICENSE_1_0.txt)

// Example 1 of using inverse gamma functions.

#include <boost/math/special_functions/gamma.hpp>

using boost::math::gamma_p_inv; // Compute x given a
//using boost::math::gamma_q_inv;
//using boost::math::gamma_p_inva; // Compute a given x
//using boost::math::gamma_q_inva;

#include <iostream>
   using std::cout;    using std::endl;
#include <iomanip>
   using std::setprecision;
#include <cmath>
   using std::sqrt;
#include <limits>

int main()
{
  cout << "Example 1 using Inverse Gamma function. " << endl;

  #ifdef BOOST_NO_CXX11_NUMERIC_LIMITS
  int max_digits10 = 2 + (boost::math::policies::digits<double, boost::math::policies::policy<> >() * 30103UL) / 100000UL;
  cout << "BOOST_NO_CXX11_NUMERIC_LIMITS is defined" << endl; 
#else 
  int max_digits10 = std::numeric_limits<double>::max_digits10;
#endif
  cout << "Show all potentially significant decimal digits std::numeric_limits<double>::max_digits10 = "
    << max_digits10 << endl; 
  cout.precision(max_digits10); // 

  double x = 1.;
  double a = 10;

  double r = boost::math::gamma_q_inv(a ,x);

  cout << " x = " << x << ", = gamma_q_inv(a,x)" << r << endl; // 
  
  return 0;
}  // int main()

/*

Output is:

*/