dolfin team mailing list archive

[Ola Skavhaug <skavhaug@xxxxxxxxx>]

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.

Ola

>
> Garth
>
>> Ola
>>
>>> Garth
>>> _______________________________________________
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>>> DOLFIN-dev@xxxxxxxxxx
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>>>
>>
>>
>>
>
>



-- 
Ola Skavhaug