/////////////////////////////////////////////////////////////// // 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 #include #include // // 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 inline void log_postfix_event(const mpfi_float_backend& val, const char* event_description) { // Print out the (relative) diameter of the interval: using namespace boost::multiprecision; number > diam; mpfi_diam(diam.backend().data(), val.data()); std::cout << "Diameter was " << diam << " after operation: " << event_description << std::endl; } template inline void log_postfix_event(const mpfi_float_backend&, 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 #include int main() { using namespace boost::multiprecision; using logged_type = logged_adaptor_t; // // 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} //] */