Re: [ublas] whole ublas matrix as vector

Subject: Re: [ublas] whole ublas matrix as vector
From: Gunter Winkler (guwi17_at_[hidden])
Date: 2009-09-06 15:11:41

Michael Norel schrieb:
> Hi all! 
>
> I still need this functionality (matrix expression as vector expression)for intensive use of ublas. 
>
>   
Please check out the latest development version from SVN: see
https://svn.boost.org/trac/boost/wiki/BoostSubversion and have a look at
experimental/sparse_view.hpp, class c_array_view. This class should
fulfill the immutable part of storage array concept. Now only a class
fulfilling the immutable part of the vector concept must be developed
which can be used to present any storage array as a read only vector.

> I need to
> 1. compare 2 matrixes with some eplison threshold like "norm_2(m1-m2) < eps"
>   
Why not using norm_inf or norm_1 for matrices?

> 2. check if the submatrix of matrix is zero like "norm_2(m1) > 0"
>   
I'd also suggest to use norm_inf or even better a customer function that
aborts the check at the first non-zero element.
> 3. find the absolute maximum element of matrix like norm_inf(m1) 
> and many others, where m1 and m2 is matrix expressions.
>
>   
Could you prepare a list of the most used matrix functions? Maybe there
are others interested. Then we could easily add a matrix-tools header
which contains such methods.

There is a trac for boost: https://svn.boost.org/trac/boost/

Here you can view, comment and create new tickets. Feel free to create a
feature request for uBLAS. Try to add an example or pseudo-code to
express the expected usage.

> Where can a i post the functionality request for such adaptor?  Or it is realy the right way to implement it myself? 
>   
The quickest way is always do it on yourself and to post the patch, an
example and a unittest here. Then I can review the code and commit it to
the repository.