Re: [Help-gsl] Octave-like indexing with the GSL

[Brian Gough]

Jordi Gutierrez Hermoso wrote:
> I was expecting to find just such a method as a matrix view with a
> clever little hack with the matrix's tda, but I cannot figure out how
> to do this. Should I just use a number of for-loops with row or
> column views, or use one of the gsl_matrix view functions for arrays,
> or is there a more clever intended way of accomplishing this?

You will have to access the memory directly for that access pattern. The 
gsl_matrix type is designed so that it can always be passed to a BLAS 
function, which means that the rows of the matrix must have a "stride" of 1.

> (Btw, I don't think I understand either the need for a
> gsl_matrix_view struct, if all it holds is a pointer to a gsl_matrix;
> is this simply to emphasise syntactically that the view owns the same
> data as another matrix?)

The implementation allows views of both const and non-const objects 
without casting.  If we had only non-const objects the extra 
"indirection" wouldn't be necessary.

--
Brian Gough
(GSL Maintainer)

Network Theory Ltd,
Publishing the GSL Manual - http://www.network-theory.co.uk/gsl/manual/