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Blitz Devel : |
From: Derrick Bass (derrick_at_[hidden])
Date: 2003-07-27 16:15:02
I recently ran across an interesting problem using Blitz and
non-standard numeric types.
The trouble is that Blitz assumes it will find functions like sqrt,
tan, etc in the std namespace, but for a user defined class or other
non-native type that is almost never true.
I've been trying to think of a good solution to this problem that would
require minimal user intervention. The best I can come up with is to
have using directives in the apply method of BZ_DEFINE_UNARY_FUNC. In
other words, replace it with something like this
static inline T_numtype
apply(T_numtype1 a)
{ BZ_USING(BZ_MATHFN_SCOPE(fun)); return fun(a); }
(BZ_USING would have to be defined) and replace the invocation of the
macro, which currently goes like this
BZ_DEFINE_UNARY_FUNC(Fn_sqrt,BZ_MATHFN_SCOPE(sqrt))
with
BZ_DEFINE_UNARY_FUNC(Fn_sqrt, sqrt)
This works for classes that have math functions defined in the global
namespace. My knowledge of C++ is a little unclear on this point: will
it work for classes that have their own namespace so long as the
namespace (or the desired function) has a using directive in effect at
the time of instantiation?
Is there a better way?
Derrick