2009/11/24 Peter Foelsche

I've the following template function:

template<typename T> T exp2(const T T0_d) { return exp(0.5*T0_d) + 2*exp(T0_d); }

I want to define this as a lambda function in place (but don't know how).

It will be used with T=double and T=MyAutomaticDerivativeClass.

#include <cmath> #include #include int main() { using namespace boost::lambda; double res = (bind(exp, 0.5 * _1) + 2 * bind(exp, _1))(0.5); } If exp is overloaded (and I guess it is, because you are going to pass both double and MyAutomaticDerivativeClass as arguments to exp), you'll need to wrap it in a polymorphic function object. struct Exp { template <class Args> struct sig : boost::tuples::element<1, Args> {}; template <class T> T operator()(T arg) const { return exp(arg); } }; int main() { using namespace boost::lambda; double res = (bind(Exp(), 0.5 * _1) + 2 * bind(Exp(), _1))(0.5); } By the way, if you have a choice, I recommend using phoenix instead of lambda. It can do everything lambda can do and even more. Roman Perepelitsa.