All, I am interested in using boost::variant to represent various field types in a performance-critical piece of software. I need the ability to perform nontrivial operations on fields, and would like to embed the loop within the visitor portion of the code for performance reasons. As a simple example, say I have
typedef std::vector<double> A; typedef std::vector<int> B; typedef boost::variant< A, B, ... > FieldVariant;
FieldVariant x, y, z; // assign x, y ... z = sqrt(x)+x*y+5.38*y^2.0;
Here I could overload the ³+² operator for various types in the FieldVariant. The overloaded + operator would implement a binary visitor which would loop over the entries and sum them (remember that the types in the variant are vectors of objects). The same thing could be done for other operators. This is highly inefficient, however, since it requires multiple loops and multiple step assembly of z. What I would like is a way to compute ³z² in a highly efficient manner. The binary visitor does not allow this Is there a good way to extend boost::variant to support efficient operations as outlined above? James