Re: [ublas] vector to diagonal matrix

From: nate (nate_at_[hidden])
Date: 2007-07-11 14:53:07

>
> what is the best way to construct a diagonal matrix from a vector (where the
> vector should be the diagonal).
>

Take a look here.

http://article.gmane.org/gmane.comp.lib.boost.ublas/3274

This is my initial attempt at a diagonal adaptor for vectors.

Since there aren't any special dispatch mechanisms for this type things are 
probably going to be slower 
than necessary.  For example

ublas::matrix<double> A(4,4);
ublas::vector<double> B(4);

prod(A,diagm(B))

probably won't be as fast as just scaling each column.  Maybe someone else can 
say more about this.

As I said before, I'm no expert.  There may already be a better way to do this 
implemented in the 
library.

Nate