Re: [ublas] indirect_array<> and resize()

Subject: Re: [ublas] indirect_array<> and resize()
From: Ralf Denzer (Ralf.Denzer_at_[hidden])
Date: 2008-09-21 08:29:52

Hi, 

> This is a general problem of references: They usually are invalid when 
> the structure of the underlying container changes. (BTW: resize does 
> not preserve the data, thus M and Mi are useless anyway.)

Ok, maybe the example was a little bit "constructed" 

> but why not
> ublas::vector<ublas::indirect_array<> > vec_ia;
> // ...
> vec_ia = ublas::vector<ublas::indirect_array<> >(10);
> the constructor is not slower than resize.

Ok, why not.

> I am still not convinced because the number of dof does not change, 
> right?

At the moment the number of dofs don't change, but maybe they will change in a future
implementation, if I increase the order of the polynomial shape functions for some 
elements in the mesh during the simulation (p-adaptivity).

> But anyway - you can try to add resize() to indirect_array (storage.hpp) 
> and see how it works. I think an additional member function will not 
> hurt ...

Ok, I can give this a try ... 
First I have to play a little bit more with indirect_array's to get some more experience with them.
You know, indirect_array's are still undocumented ... let's see ...

Bye 

Ralf

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