On Thu, 2012-06-28 at 19:38 +0200, Marc Glisse wrote:
On Thu, 28 Jun 2012, Mario Mulansky wrote:
My test case is to use floating point multiprecision types as the basis for our odeint library (www.odeint.com). As odeint is fully templatized I could just plug in, say, the cpp_dec_float_50 and the basic routines worked out of the box. The only problem I had was that there seems to be no support for min / max functions for expressions of multiprecision types. So can not write
x = max( a+b , a*b )
x = max<cpp_dec_float_50>( a+b , a*b ) maybe?
(assuming they don't overload max for this library)
I think this would work, but I don't want to do that because then any user defined non-templatized function would not be found (see example below). I think the better way is an explicit cast of the arguments: max( static_cast< mp_type >( a+b ) , static_cast< mp_type >( a*b ) ); as also written in the MP introduction as I just found out. Example, where the user defined function is not used because it isn't templatized: #include <iostream> struct my_type { }; bool operator <( const my_type x , const my_type y ) { return true; } // for std::max to compile... bool max( const my_type x , const my_type y ) { std::cout << "test" << std::endl; }; int main() { my_type a , b; using std::max; max( a , b ); // calls user defined max max<my_type>( a , b ); // calls std::max, not good // user defined max, I think that's the right way: max( static_cast<my_type>(a) , static_cast<my_type>(b) ); }