https://svn.boost.org/trac10/ticket/13608 <p> The version of boost that I'm using is through macports. I believe that there is a typo in multiprecision/mpfi.hpp. On line 478, digits2_2_10 should be replaced by digits10_2_2. </p> <p> The original code is </p> <p> void precision(unsigned digits10) BOOST_NOEXCEPT { </p> <blockquote> <p> mpfi_set_prec(this-&gt;m_data, multiprecision::detail::digits2_2_10((digits10))); </p> </blockquote> <p> } </p> <p> The corrected code should be </p> <p> void precision(unsigned digits10) BOOST_NOEXCEPT { </p> <blockquote> <p> mpfi_set_prec(this-&gt;m_data, multiprecision::detail::digits10_2_2((digits10))); </p> </blockquote> <p> } </p> <p> This change means that with and without an argument, precision reverses the digits operation. Moreover, this matches the corresponding lines in mpfr.hpp. </p> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/13608 Trac 1.4.3 John Maddock Sun, 17 Jun 2018 16:56:52 GMT https://svn.boost.org/trac10/ticket/13608#comment:1 https://svn.boost.org/trac10/ticket/13608#comment:1 <ul> <li><strong>status</strong> <span class="trac-field-old">new</span> → <span class="trac-field-new">closed</span> </li> <li><strong>resolution</strong> → <span class="trac-field-new">fixed</span> </li> </ul> <p> Yep, that's been fixed in develop already and is scheduled for the next release. </p> Ticket