Geoffrey Irving said: (by the date of Tue, 13 Jun 2006 09:30:39 -0700)
I would suggest that instead of trying to make an extremely general vector class, it'd be better to make an extremely specific vector class, together with an extremely general way to other vector classes.
Specifically, you can make vector3 (or vector<3>, perhaps) a straightforward single unit Euclidean vector. It can have L2 norms and L^inf norms and cross products and all the operations that are undefined for vectors with components of different units. Then we could define a vector space variant of boost::operators to convert any tuple-like type into a vector space type.
I like this idea very much. Not general, but specific, with underlyings exportable to other classes.
If you wanted phase space, you'd do something like this:
template<class Q,class P> class phase_vector:public boost::vector_operators<phase_vector>; <snip>
I'm afraid that this example is too simplified. phase_vector would need the ability to be multiplied by matrix_with_units (weird name I know ;) - but it's rather not a phase_matrix)
and the vector_operators class would fill in scalar multiplication and addition-related operators. In my opinion, this would be far more useful than writing phase space as
vector<m,m,m,kg_m_div_s,kg_m_div_s,kg_m_div_s>
indeed it would be more useful, once get right. But I have the impression that it will be more difficult than getting vector<3> right, or getting units system right :/ PS: I like vector<3> , I think that Andy can't argue with this name :> In fact all this discuccion is great for deciding about a specification of such a library. When specification is agreed upon, then implementation should be easy enough :) -- Janek Kozicki |