Re: [eigen] conservative resize ...

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

I had a look: the code still is quite small, not yet too big to stay
in Matrix.h.

The forward-decl of ei_conservative_resize_like_impl is a little ugly,
true, what you could do is to defer the body of conservativeResizeLike
until after the class Matrix definition, so you don't need to
forward-declare ei_conservative_resize_like_impl.

Benoit

2009/9/8 Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>:
> Sorry again for the gcc bugs.... they should be fixed by now.
>
> I am still confused, whether it is a good idea to start polluting the
> Matrix.h with expressions and forward declarations.
>
> - Hauke
>
> On Mon, Sep 7, 2009 at 5:50 PM, Hauke Heibel<hauke.heibel@xxxxxxxxxxxxxx> wrote:
>> ok, it's in.
>>
>> On Mon, Sep 7, 2009 at 4:47 PM, Benoit Jacob<jacob.benoit.1@xxxxxxxxx> wrote:
>>> Ah, the meta-selector to choose between the two paths for that function..
>>>
>>> Since that's specific to that function, it shouldn't go in
>>> XprHelpers.h, instead it should go in the same file where (the rest
>>> of) that function is implemented.
>>>
>>> The way we usually do it is rather:
>>>
>>> template <typename Derived, typename OtherDerived, int IsVector =
>>> Derived::IsVectorAtCompileTime>
>>> struct resize_helper
>>> {
>>>  static void run(const Eigen::MatrixBase<Derived>& _this, const
>>> Eigen::MatrixBase<OtherDerived>& other)
>>>  {
>>>   std::cout << "Matrix assignment" << std::endl;
>>>  }
>>> };
>>>
>>> template <typename Derived, typename OtherDerived>
>>> struct resize_helper<Derived, OtherDerived,true>
>>> {
>>>  template <typename Derived, typename OtherDerived>
>>>  static void run(const Eigen::MatrixBase<Derived>& _this, const
>>> Eigen::MatrixBase<Derived>& other)
>>>  {
>>>   std::cout << "Vector assignment" << std::endl;
>>>  }
>>> };
>>>
>>> Then you can call it like resize_helper(a,b) and let all the template
>>> parameters be resolved implicitly. This is less error-prone than
>>> having to manually specify IsVector. Also note how we usually don't
>>> put "xpr" in names since otherwise we'd have "xpr" about everywhere.
>>>
>>> Benoit
>>>
>>> 2009/9/7 Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>:
>>>> On Mon, Sep 7, 2009 at 4:28 PM, Benoit Jacob<jacob.benoit.1@xxxxxxxxx> wrote:
>>>>> There already is: MatrixBase<T>::IsVectorAtCompileTime.
>>>>
>>>> yes, i know.
>>>>
>>>> i  was thinking about something like this...
>>>>
>>>> template <int IsVector>
>>>> struct resize_xpr_helper
>>>> {
>>>>  template <typename Derived, typename OtherDerived>
>>>>  static void run(const Eigen::MatrixBase<Derived>& _this, const
>>>> Eigen::MatrixBase<OtherDerived>& other)
>>>>  {
>>>>    std::cout << "Matrix assignment" << std::endl;
>>>>  }
>>>> };
>>>>
>>>> template <>
>>>> struct resize_xpr_helper<1>
>>>> {
>>>>  template <typename Derived, typename OtherDerived>
>>>>  static void run(const Eigen::MatrixBase<Derived>& _this, const
>>>> Eigen::MatrixBase<Derived>& other)
>>>>  {
>>>>    std::cout << "Vector assignment" << std::endl;
>>>>  }
>>>> };
>>>>
>>>> - hauke
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>
>
>