https://svn.boost.org/trac10/ticket/5015 <p> File: boost\math\special_functions\detail\ibeta_inverse.hpp Function: T ibeta_inv_imp(T a, T b, T p, T q, const Policy&amp; pol, T* py) Line: 480-503. When ((q or p is equal to 0) or (a and b equal to 1)) and invert is true the return value is not reverted. It can be fixed by placing these checks before </p> <blockquote> <p> if(a == 0.5f) { </p> <blockquote> <p> std::swap(a, b); std::swap(p, q); invert = !invert; </p> </blockquote> <p> } </p> </blockquote> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/5015 Trac 1.4.3 anonymous Mon, 27 Dec 2010 12:25:58 GMT https://svn.boost.org/trac10/ticket/5015#comment:2 https://svn.boost.org/trac10/ticket/5015#comment:2 <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> (In <a class="changeset" href="https://svn.boost.org/trac10/changeset/67469" title="Fix bug in special-case handling of ibeta_inv. Fix concept test ...">[67469]</a>) Fix bug in special-case handling of ibeta_inv. Fix concept test failures with mpfr_class in legendre.hpp and non_central_t.hpp. Fixes <a class="closed ticket" href="https://svn.boost.org/trac10/ticket/5015" title="#5015: Bugs: ibeta_inv_imp handling cases when (q == 0 or p == 0) or (a == 1 and b == 1) (closed: fixed)">#5015</a>. </p> Ticket