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Subject: Re: [ublas] Constructors in fixed_vectors.
From: Nasos Iliopoulos (nasos_i_at_[hidden])
Date: 2015-08-16 22:55:04


Your are right we should also provide an initialization list
constructor. Last time I checked initialization lists (like a year ago)
were not treated properly by all compilers and that's the reason the
implementation is the way it is in uBlas. I am pretty sure the standard
implementation of std:array will have a more universally accepted approach.

My only concern is that dynamic containers in uBlas already provide the
functionality of initializing with a value and we should make sure we
keep this feature.

I just created this branch if you want to work on:
https://github.com/uBLAS/ublas/tree/feature/ublas00003_fixed_containers_initialization_list_constructor

I can check with various versions of clang and g++ within the week if
those work before we merge to develop.

-Nasos

On 08/12/2015 06:55 PM, Joaquim Duran Comas wrote:
> Hello,
>
> These days, I'm fixing the issues in tests when they are compiled
> using MSCV compiler.
>
> I've an issue with the constructors of fixed_vector. In fixed_vector,
> MSVC compiler gets confused with these constructors:
>
> /// \brief Constructor of a fixed_vector with a unique initial value
> /// \param init value to assign to each element of the vector
> BOOST_UBLAS_INLINE
> fixed_vector (const value_type &init):
> vector_container<self_type> (),
> data_ () {
> data_.fill( init );
> }
>
> and
> #if defined(BOOST_MSVC)
> // This may or may not work. Maybe use this for all instead only for MSVC
> template <typename... U>
> fixed_vector(U&&... values) :
> vector_container<self_type> (),
> data_{{ std::forward<U>(values)... }} {}
> #else
> template <typename... Types>
> fixed_vector(value_type v0, Types... vrest) :
> vector_container<self_type> (),
> data_{ { v0, vrest... } } {}
> #endif
>
> because, constructing a vector and providing just an unique initial
> value, any of these constructors could be called and the compiler
> reports a warning.
>
> I propose change the second constructor by providing an
> inilialization_list (instead of a variadiric template), where type of
> elements of the list can be enforced as well as the length of the list.
>
> Joaquim Duran
>
>
>
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