dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Ola Skavhaug wrote:
> On Wed, Aug 19, 2009 at 11:16 PM, Garth N. Wells<gnw20@xxxxxxxxx> wrote:
> > Ola Skavhaug wrote:
> > > On Wed, Aug 19, 2009 at 8:30 PM, Garth N. Wells<gnw20@xxxxxxxxx> wrote:
> > > > I didn't realise until recently that storage in std::vector is
> > > > guaranteed by the C++ standard to be contiguous (versus only being
> > > > contiguous in all known implementations). Using this, I think that we
> > > > can have safer and cleaner code by using more std::vector in the linear
> > > > algebra interface. For example, we could have
> > > >
> > > >  GenericVector::get(std::vector<double>& );
> > > >  GenericVector::set(const std::vector<double>& );
> > > >
> > > > instead of
> > > >
> > > >  GenericVector::get(double* x);
> > > >  GenericVector::set(const double* x);
> > > >
> > > > For backends that want a pointer to an array, we can pass &x[0]. Any
> > > > opinions?
> > > I completely agree. I didn't know this either, but Google told me
> > > you're right, .i.e, that C++03 guarantees contiguity. Looking forward
> > > to C++0x when arrays will be contiguous as well.
> > Not sure you mean about arrays. Do you mean multi-dimensional arrays?
>
> std::array or boost::tr1::array as it is called today. See:
> http://herbsutter.wordpress.com/2008/04/07/cringe-not-vectors-are-guaranteed-to-be-contiguous/
> and
> http://groups.google.com/group/comp.lang.c++.moderated/browse_thread/thread/baa9b98c83e0b412?pli=1
>
> boost::tr1::array are fixed size, and maps more directly to native c++
> arrays. This might make issues like grabbing raw pointers less
> complicated.

Should we template get/set functions so one can use a std::vector or a 
boost::array, or even a boost::mult_array?

Garth

> Ola
>
> > Garth
> >
> > > Ola
> > >
> > > > Garth
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