46 lines
1.4 KiB
C++
46 lines
1.4 KiB
C++
// Copyright John Maddock 2007.
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// Copyright Paul A. Bristow 2010
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// Use, modification and distribution are subject to the
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// Boost Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// Note that this file contains quickbook mark-up as well as code
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// and comments, don't change any of the special comment mark-ups!
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#include <iostream>
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using std::cout; using std::endl;
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// Setting (approximate) precision 25 bits in a single function call using make_policy.
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//[policy_ref_snip11
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#include <boost/math/distributions/normal.hpp>
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using boost::math::normal_distribution;
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using namespace boost::math::policies;
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const int bits = 25; // approximate precision.
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double q = quantile(
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normal_distribution<double, policy<digits2<bits> > >(),
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0.05); // 5% quantile.
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//] //[/policy_ref_snip11]
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int main()
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{
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std::streamsize p = 2 + (bits * 30103UL) / 100000UL;
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// Approximate number of significant decimal digits for 25 bits.
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cout.precision(p);
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cout << bits << " binary bits is approoximately equivalent to " << p << " decimal digits " << endl;
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cout << "quantile(normal_distribution<double, policy<digits2<25> > >(), 0.05 = "
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<< q << endl; // -1.64485
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}
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/*
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Output:
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25 binary bits is approoximately equivalent to 9 decimal digits
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quantile(normal_distribution<double, policy<digits2<25> > >(), 0.05 = -1.64485363
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*/
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