I am using the multiprecision library from /sandbox/big_number compiling with boost 1.49.0. Specifically, I am using cpp_int. I can successfully compile and run the following example: #include <boost/multiprecision/cpp_int.hpp> using namespace boost::multiprecision; cpp_int u = 1; for(unsigned i = 1; i <= 100; ++i) u *= i; std::cout << u << std::endl; // prints 100! which I obtained from: https://svn.boost.org/svn/boost/sandbox/big_number/libs/multiprecision/doc/h... When I add the following code: cpp_int x; x = pow( u, 2 ); I receive the following compiler error (g++ 4.1.2): ./boost/boost/multiprecision/detail/functions/pow.hpp: In function ‘void boost::multiprecision::default_ops::eval_pow(T&, const T&, const U&) [with T = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, U = int]’: ./boost/boost/multiprecision/detail/default_ops.hpp:1250: instantiated from ‘void boost::multiprecision::detail::pow_funct<Backend>::operator()(Backend&, const Backend&, const Arithmetic&) const [with Arithmetic = int, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >]’ ./boost/boost/multiprecision/mp_number.hpp:1089: instantiated from ‘void boost::multiprecision::mp_number<Backend, ExpressionTemplates>::do_assign_function_2(const F&, const Exp1&, const Exp2&, const boost::multiprecision::detail::terminal&, const boost::multiprecision::detail::terminal&) [with F = boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, Exp1 = boost::multiprecision::detail::mp_exp<boost::multiprecision::detail::terminal, boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, void, void>, Exp2 = boost::multiprecision::detail::mp_exp<boost::multiprecision::detail::terminal, int, void, void>, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ ./boost/boost/multiprecision/mp_number.hpp:1084: instantiated from ‘void boost::multiprecision::mp_number<Backend, ExpressionTemplates>::do_assign_function(const Exp&, const mpl_::int_<3>&) [with Exp = boost::multiprecision::detail::mp_exp<boost::multiprecision::detail::function, boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, int>, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ ./boost/boost/multiprecision/mp_number.hpp:973: instantiated from ‘void boost::multiprecision::mp_number<Backend, ExpressionTemplates>::do_assign(const Exp&, const boost::multiprecision::detail::function&) [with Exp = boost::multiprecision::detail::mp_exp<boost::multiprecision::detail::function, boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, int>, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ ./boost/boost/multiprecision/mp_number.hpp:570: instantiated from ‘void boost::multiprecision::mp_number<Backend, ExpressionTemplates>::do_assign(const boost::multiprecision::detail::mp_exp<tag, Arg1, Arg2, Arg3>&, const mpl_::true_&) [with tag = boost::multiprecision::detail::function, Arg1 = boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, Arg2 = boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, Arg3 = int, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ ./boost/boost/multiprecision/mp_number.hpp:95: instantiated from ‘boost::multiprecision::mp_number<Backend, ExpressionTemplates>& boost::multiprecision::mp_number<Backend, ExpressionTemplates>::operator=(const boost::multiprecision::detail::mp_exp<tag, Arg1, Arg2, Arg3>&) [with tag = boost::multiprecision::detail::function, Arg1 = boost::multiprecision::detail::pow_funct<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> > >, Arg2 = boost::multiprecision::mp_number<boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, true>, Arg3 = int, Backend = boost::multiprecision::backends::cpp_int_backend<0u, true, std::allocator<unsigned int> >, bool ExpressionTemplates = true]’ vcp_translator_test.cpp:24: instantiated from here ./boost/boost/multiprecision/detail/functions/pow.hpp:89: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>’ Different invocations of pow with the arbitrary precision argument as the base, exponent, or both yield different compiler errors, but all of them seem to be broken. Am I doing something wrong? Is there some other fast way to achieve exponentiation with this library? Thanks, Ryan