Re: uBLAS: Can I make my vector<...> derived class 'copy constructible' ?

From: speedsnaii (speedsnaii_at_[hidden])
Date: 2003-03-11 06:37:11

Hi Joerg,

> 
> > I think my derived class is not 'copy constructible'
> > and 'assignable'.
> > Is there a simple way to fix this?
> 
> I believe yes: we could drop the requirement that assignments have 
to be
> size conformant. But this requirement is pretty useful when doing 
basic
> linear algebra IMHO. So I'd like to hear other opinions...
> 

Thank you, this will work for me. But still a question left:

It seems even when I use the copy constructor of a ublas::vector the 
values are copied using the assignment operator. Shouldn't they be 
copied using their copy constructor instead? In this case also 
ublas::vector would work as same as std::vector.

It is meaningful, when the operator= would not work since the 
contained vectors of course are not the same size. This problem will 
arise whenever doing 'vector of vector' or similar.

> > (I am not even sure whether this is a uBLAS matter. So please 
simple
> > tell me, and I will try to learn the missing parts.)
> 
> It's definitely an ublas matter: should we increase standard 
compatibility
> or stay with the size conformance restriction.
> 

I think vector is copy constructible, if the element type also is 
copy constructible, isn't it? And if I use a vector as a element type 
(which is copy constructible I think), there should be no problem. No 
need to give up current size conformance restriction behaviour for 
assignment.

What do you think?

Regards,
Roland