Re: ublas: vector<>::upper_bound()

From: Kresimir Fresl (fresl_at_[hidden])
Date: 2002-03-10 11:34:44

jhrwalter wrote:

> May be upper_bound()/lower_bound() are bad names.

It seems that they are. At least, they are misleading.

> These member are essential for the iterators of binary operation 
> expression templates: [...]

I think (hope) that I see what you mean: if
---------------------------------------------------------------
     numerics::unit_vector<double> u3 (8, 3);
     numerics::unit_vector<double> u4 (8, 5);

     cout << (u3+u4).begin().index() << "  "
             << (u3+u4).end().index() << endl;
----------------------------------------------------------------
is compiled with -DNDEBUG (which on g++ means
`use expression templates'), the output is: `3  6',
and when NDEBUG is not defined (ie., `don't use ETs'),
output is `0  8'.

> OTOH do you know a better name for the existing beasts?
 > [lower_bound()/upper_bound()]

Hmm. Maybe simply `first()' and `last()'?

>>[2] `find()', `lower_bound()' and `upper_bound()' are listed
>>in interface of `numerics::vector<>' in docs, but I didn't find
>>their description (AFAIK functions `find()' etc. are described
>>only in docs for `compressed_array<>'; their descriptions are
>>similar to those for `std::map<>').

> Yep. I'm not sure, if these members aren't an implementation detail 
> only.

Well, I have no idea how to use them in my `real' code ;o).
But I guess that they must be `public' (ie. part of the interface) so
that expression templates can access them. Maybe you should mark
them `For internal use only' in docs to prevent people like me
to play with them ;o).

> Thanks for your effort.

Nothing at all. I hope that soon we'll have efficient and reliable
vector/matrix library.

fres