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///////////////////////////////////////////////////////////////
// Copyright 2013 John Maddock. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
//[logged_adaptor
#include <iostream>
#include <iomanip>
#include <boost/multiprecision/fwd.hpp>
//
// Begin by overloading log_postfix_event so we can capture each arithmetic event as it happens,
// unfortunately this must occur BEFORE we include the full header, so just include the forward
// declarations and define our overloads for now. Note that in some cases we may need to just
// declare the overloads here, and define them once the types become concrete:
//
namespace boost {
namespace multiprecision {
template <unsigned D>
inline void log_postfix_event(const mpfi_float_backend<D>& val, const char* event_description)
{
// Print out the (relative) diameter of the interval:
using namespace boost::multiprecision;
number<mpfr_float_backend<D> > diam;
mpfi_diam(diam.backend().data(), val.data());
std::cout << "Diameter was " << diam << " after operation: " << event_description << std::endl;
}
template <unsigned D, class T>
inline void log_postfix_event(const mpfi_float_backend<D>&, const T&, const char* event_description)
{
// This version is never called in this example.
}
}
} // namespace boost::multiprecision
//
// Now we can include the actual multiprecision headers and make the types concrete:
//
#include <boost/multiprecision/mpfi.hpp>
#include <boost/multiprecision/logged_adaptor.hpp>
int main()
{
using namespace boost::multiprecision;
using logged_type = logged_adaptor_t<mpfi_float_50>;
//
// Test case deliberately introduces cancellation error, relative size of interval
// gradually gets larger after each operation:
//
logged_type a = 1;
a /= 10;
for(unsigned i = 0; i < 13; ++i)
{
logged_type b = a * 9;
b /= 10;
a -= b;
}
std::cout << "Final value was: " << a << std::endl;
return 0;
}
//]
/*
//[logged_adaptor_output
Diameter was -0 after operation: Default construct
Diameter was 0 after operation: Assignment from arithmetic type
Diameter was 3.34096e-51 after operation: /=
Diameter was -0 after operation: Default construct
Diameter was 5.93948e-51 after operation: *
Diameter was 7.42435e-51 after operation: /=
Diameter was 1.00229e-49 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 1.00229e-49 after operation: *
Diameter was 1.02085e-49 after operation: /=
Diameter was 1.92105e-48 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 1.92105e-48 after operation: *
Diameter was 1.92279e-48 after operation: /=
Diameter was 3.65156e-47 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 3.65156e-47 after operation: *
Diameter was 3.65163e-47 after operation: /=
Diameter was 6.93803e-46 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 6.93803e-46 after operation: *
Diameter was 6.93803e-46 after operation: /=
Diameter was 1.31823e-44 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 1.31823e-44 after operation: *
Diameter was 1.31823e-44 after operation: /=
Diameter was 2.50463e-43 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 2.50463e-43 after operation: *
Diameter was 2.50463e-43 after operation: /=
Diameter was 4.7588e-42 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 4.7588e-42 after operation: *
Diameter was 4.7588e-42 after operation: /=
Diameter was 9.04171e-41 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 9.04171e-41 after operation: *
Diameter was 9.04171e-41 after operation: /=
Diameter was 1.71793e-39 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 1.71793e-39 after operation: *
Diameter was 1.71793e-39 after operation: /=
Diameter was 3.26406e-38 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 3.26406e-38 after operation: *
Diameter was 3.26406e-38 after operation: /=
Diameter was 6.20171e-37 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 6.20171e-37 after operation: *
Diameter was 6.20171e-37 after operation: /=
Diameter was 1.17832e-35 after operation: -=
Diameter was -0 after operation: Default construct
Diameter was 1.17832e-35 after operation: *
Diameter was 1.17832e-35 after operation: /=
Diameter was 2.23882e-34 after operation: -=
Final value was: {1e-14,1e-14}
//]
*/
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