I'd like to get some feedback on a multiprecision arithmetic library I've been preparing for possible Boost inclusion. The code is in the sandbox under the "big_number" directory. Docs can be viewed online here: http://svn.boost.org/svn/boost/sandbox/big_number/libs/multiprecision/doc/ht...
It looks really good!
One question: is it possible to an mp_number from one backend to another one in some other backend (without having to go mp_number1 -> string -> mp_number2 of course)?
Maybe ;-) An mp_number is copy-constructible from anything that the backend is copy-constructible from. So related types typically interconvert - for example all the GMP supported types interconvert, and can also be constructed from the raw GMP C struct types. However, unrelated types do not interconvert, so for example a number based on the cpp_float backend doesn't convert to one based on the GMP MPF backend. Given that their internal data structures are quite different I don't see how they can interconvert either - except via a lexical_cast. HTH, John.