dolfin team mailing list archive

[Ola Skavhaug <skavhaug@xxxxxxxxx>]

On Wed, Aug 19, 2009 at 11:45 PM, Garth N. Wells<gnw20@xxxxxxxxx> wrote:
>
>
> 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

That would be nice if we use both boost arrays and std vectors in DOLFIN.
Just templating the methods, like we did in XMLFile?

Ola

>> Ola
>>
>>> Garth
>>>
>>>> Ola
>>>>
>>>>> Garth
>>>>> _______________________________________________
>>>>> DOLFIN-dev mailing list
>>>>> DOLFIN-dev@xxxxxxxxxx
>>>>> http://www.fenics.org/mailman/listinfo/dolfin-dev
>>>>>
>>>>
>>>>
>>>
>>
>>
>>
>
>



-- 
Ola Skavhaug