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// Copyright John Maddock 2007.
// 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)
// Note that this file contains quickbook mark-up as well as code
// and comments, don't change any of the special comment mark-ups!
//[policy_eg_10
/*`
To understand how the rounding policies for
the discrete distributions can be used, we'll
use the 50-sample binomial distribution with a
success fraction of 0.5 once again, and calculate
all the possible quantiles at 0.05 and 0.95.
Begin by including the needed headers (and some using statements for conciseness):
*/
#include <iostream>
using std::cout; using std::endl;
using std::left; using std::fixed; using std::right; using std::scientific;
#include <iomanip>
using std::setw;
using std::setprecision;
#include <boost/math/distributions/binomial.hpp>
/*`
Next we'll bring the needed declarations into scope, and
define distribution types for all the available rounding policies:
*/
// Avoid
// using namespace std; // and
// using namespace boost::math;
// to avoid potential ambiguity of names, like binomial.
// using namespace boost::math::policies; is small risk, but
// the necessary items are brought into scope thus:
using boost::math::binomial_distribution;
using boost::math::policies::policy;
using boost::math::policies::discrete_quantile;
using boost::math::policies::integer_round_outwards;
using boost::math::policies::integer_round_down;
using boost::math::policies::integer_round_up;
using boost::math::policies::integer_round_nearest;
using boost::math::policies::integer_round_inwards;
using boost::math::policies::real;
using boost::math::binomial_distribution; // Not std::binomial_distribution.
typedef binomial_distribution<
double,
policy<discrete_quantile<integer_round_outwards> > >
binom_round_outwards;
typedef binomial_distribution<
double,
policy<discrete_quantile<integer_round_inwards> > >
binom_round_inwards;
typedef binomial_distribution<
double,
policy<discrete_quantile<integer_round_down> > >
binom_round_down;
typedef binomial_distribution<
double,
policy<discrete_quantile<integer_round_up> > >
binom_round_up;
typedef binomial_distribution<
double,
policy<discrete_quantile<integer_round_nearest> > >
binom_round_nearest;
typedef binomial_distribution<
double,
policy<discrete_quantile<real> > >
binom_real_quantile;
/*`
Now let's set to work calling those quantiles:
*/
int main()
{
cout <<
"Testing rounding policies for a 50 sample binomial distribution,\n"
"with a success fraction of 0.5.\n\n"
"Lower quantiles are calculated at p = 0.05\n\n"
"Upper quantiles at p = 0.95.\n\n";
cout << setw(25) << right
<< "Policy"<< setw(18) << right
<< "Lower Quantile" << setw(18) << right
<< "Upper Quantile" << endl;
// Test integer_round_outwards:
cout << setw(25) << right
<< "integer_round_outwards"
<< setw(18) << right
<< quantile(binom_round_outwards(50, 0.5), 0.05)
<< setw(18) << right
<< quantile(binom_round_outwards(50, 0.5), 0.95)
<< endl;
// Test integer_round_inwards:
cout << setw(25) << right
<< "integer_round_inwards"
<< setw(18) << right
<< quantile(binom_round_inwards(50, 0.5), 0.05)
<< setw(18) << right
<< quantile(binom_round_inwards(50, 0.5), 0.95)
<< endl;
// Test integer_round_down:
cout << setw(25) << right
<< "integer_round_down"
<< setw(18) << right
<< quantile(binom_round_down(50, 0.5), 0.05)
<< setw(18) << right
<< quantile(binom_round_down(50, 0.5), 0.95)
<< endl;
// Test integer_round_up:
cout << setw(25) << right
<< "integer_round_up"
<< setw(18) << right
<< quantile(binom_round_up(50, 0.5), 0.05)
<< setw(18) << right
<< quantile(binom_round_up(50, 0.5), 0.95)
<< endl;
// Test integer_round_nearest:
cout << setw(25) << right
<< "integer_round_nearest"
<< setw(18) << right
<< quantile(binom_round_nearest(50, 0.5), 0.05)
<< setw(18) << right
<< quantile(binom_round_nearest(50, 0.5), 0.95)
<< endl;
// Test real:
cout << setw(25) << right
<< "real"
<< setw(18) << right
<< quantile(binom_real_quantile(50, 0.5), 0.05)
<< setw(18) << right
<< quantile(binom_real_quantile(50, 0.5), 0.95)
<< endl;
} // int main()
/*`
Which produces the program output:
[pre
policy_eg_10.vcxproj -> J:\Cpp\MathToolkit\test\Math_test\Release\policy_eg_10.exe
Testing rounding policies for a 50 sample binomial distribution,
with a success fraction of 0.5.
Lower quantiles are calculated at p = 0.05
Upper quantiles at p = 0.95.
Policy Lower Quantile Upper Quantile
integer_round_outwards 18 31
integer_round_inwards 19 30
integer_round_down 18 30
integer_round_up 19 31
integer_round_nearest 19 30
real 18.701 30.299
]
*/
//] //[policy_eg_10] ends quickbook import.
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