is there a way to convert from cpp_int to cpp_dec_float and viceversa?
Since I've to use the modulus between two cpp_dec_float which I know they're integers but I need sqrt before and trying to run % with them gives:
You could use fmod in place of the % operator? There is an explicit conversion from cpp_int to cpp_dec_float, but no conversion in the opposite direction (in general it's unsafe). I guess we should try and figure out a generic way to implement the equivalent of iround/itrunc for that. /usr/local/include/boost/multiprecision/number.hpp: In member function
‘void boost::multiprecision::number<Backend, ExpressionTemplates>::do_assign(const Exp&, const boost::multiprecision::detail::modulus_immediates&) [with Exp = boost::multiprecision::detail::expression<boost::multiprecision::detail::modulus_immediates, boost::multiprecision::number<boost::multiprecision::backends::cpp_dec_float<100u, int, void>, et_on>, boost::multiprecision::number<boost::multiprecision::backends::cpp_dec_float<100u, int, void>, et_on>, void, void>, Backend = boost::multiprecision::backends::cpp_dec_float<100u, int, void>, boost::multiprecision::expression_template_option ExpressionTemplates = et_on]’: /usr/local/include/boost/multiprecision/number.hpp:680: instantiated from ‘void boost::multiprecision::number<Backend, ExpressionTemplates>::do_assign(const boost::multiprecision::detail::expression<tag, Arg1, Arg2, Arg3, Arg4>&, const mpl_::true_&) [with tag = boost::multiprecision::detail::modulus_immediates, Arg1 = boost::multiprecision::number<boost::multiprecision::backends::cpp_dec_float<100u, int, void>, et_on>, Arg2 = boost::multiprecision::number<boost::multiprecision::backends::cpp_dec_float<100u, int, void>, et_on>, Arg3 = void, Arg4 = void, Backend = boost::multiprecision::backends::cpp_dec_float<100u, int, void>, boost::multiprecision::expression_template_option ExpressionTemplates = et_on]’ /usr/local/include/boost/multiprecision/number.hpp:134: instantiated from ‘typename boost::enable_if<boost::is_convertible<typename boost::multiprecision::detail::expression<tag, Arg1, Arg2, Arg3, Arg4>::result_type, boost::multiprecision::number<Backend, ExpressionTemplates> >, boost::multiprecision::number<Backend, ExpressionTemplates>&>::type boost::multiprecision::number<Backend, ExpressionTemplates>::operator=(const boost::multiprecision::detail::expression<tag, Arg1, Arg2, Arg3, Arg4>&) [with tag = boost::multiprecision::detail::modulus_immediates, Arg1 = boost::multiprecision::number<boost::multiprecision::backends::cpp_dec_float<100u, int, void>, et_on>, Arg2 = boost::multiprecision::number<boost::multiprecision::backends::cpp_dec_float<100u, int, void>, et_on>, Arg3 = void, Arg4 = void, Backend = boost::multiprecision::backends::cpp_dec_float<100u, int, void>, boost::multiprecision::expression_template_option ExpressionTemplates = et_on]’ /usr/local/include/boost/multiprecision/number.hpp:181: instantiated from ‘boost::multiprecision::number<Backend, ExpressionTemplates>::number(const boost::multiprecision::detail::expression<tag, Arg1, Arg2, Arg3, Arg4>&, typename boost::enable_if_c<boost::is_convertible<typename boost::multiprecision::detail::expression<tag, Arg1, Arg2, Arg3, Arg4>::result_type,boost::multiprecision::number<Backend, ExpressionTemplates> >::value, void>::type*) [with tag = boost::multiprecision::detail::modulus_immediates, Arg1 = boost::multiprecision::number<boost::multiprecision::backends::cpp_dec_float<100u, int, void>, et_on>, Arg2 = boost::multiprecision::number<boost::multiprecision::backends::cpp_dec_float<100u, int, void>, et_on>, Arg3 = void, Arg4 = void, Backend = boost::multiprecision::backends::cpp_dec_float<100u, int, void>, boost::multiprecision::expression_template_option ExpressionTemplates = et_on]’ test.cpp:20: instantiated from here /usr/local/include/boost/multiprecision/number.hpp:912: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’
Uh. That's a horrible message :-( I'll see if there's a way to make that any better. Regards, John.