Re: GSL containers: was Re: [Help-gsl] Linear least squares, webpages and the next release

[John D Lamb <J dot D dot Lamb at johndlamb dot net>]

On 05/11/15 04:41, Patrick Alken wrote:
> I agree that stuff is very confusing. I also wonder how much of it is
> needed. In my work I've only ever used the double and complex versions
> of gsl_vector/gsl_matrix. Most of the routines in GSL only work with
> double vectors, with a few extended to complex double (linalg,eigen for
> example).
>
> Do we really need gsl_vector's for int/short/uint/long/etc?

I have used gsl_vector_long on occasion.

> On 11/04/2015 06:43 PM, Gerard Jungman wrote:
> > On 11/04/2015 04:16 PM, Patrick Alken wrote:
> > > I think this is a good idea. Would you be able/willing to design a
> > > new gsl_vector_view structure? Even something very preliminary which
> > > we could iterate a bit to get it to a nice mature status. I, or
> > > someone else, could then run with it and begin the tedious work of
> > > converting all the existing interfaces.
> > >
> > > Patrick
> >
> > If anybody can think of a better way to do the generalizations,
> > besides the current preprocessor implementation, that would be
> > great. I have nothing against the preprocessor, but the current
> > framework makes it nearly impossible to actually read the code.

Ruby? Python? In the absence of C++ templates I usually use one or 
other. Python is likely more readable to C programmers.

> > The current impl is like traits classes, but where the traits
> > are all defined in a very rudimentary way in "templates_on.h".
> > It is impossible to tell what traits are available, which ones
> > are required, and how the separate traits are associated with
> > the basic types at the point where the macros are invoked.

Iâm happy to help if someone can suggest a basic workable design. I can 
certainly change the alloc functions to use a pool allocator internally. 
And, since I mostly use C++, I can see the logic of initialising vector 
structs. But I canât think of a good design that wonât break a lot of 
user code. One of the features of the GSL is that you canât alloc a 
vector of size 0 without writing a custom allocator. It would be easy to 
change gsl_vector_alloc. But I canât even think how to do that and 
guarantee not to break user code.

--
John D Lamb