Re: [ublas] [Question] sub-matrix by columns

Subject: Re: [ublas] [Question] sub-matrix by columns
From: Matthias Walter (xammy_at_[hidden])
Date: 2010-11-24 10:20:03

On 11/24/2010 09:59 AM, Marcel Rehberg wrote:
> Hi,
>
> On Wed, 24 Nov 2010 15:39:57 +0100, Matwey V. Kornilov
> <matwey.kornilov_at_[hidden]> wrote:
>
>>
>> Hi Marcel,
>>
>> What version of gcc do you use?
>
> gcc (Debian 4.3.2-1.1) 4.3.2
>
> And as far as I understand the documentation I need to matrices for
> indexing, one for the rows and one for the columns. So my minimum
> example to extract the first column of a 2xN matrix (named grid here)
> would be:
>
> ublas::matrix<unsigned> index1(2,1);
> ublas::matrix<unsigned> index2(2,1);

For my last project I used

boost::numeric::ublas::indirect_array <vector_type>

as an indext type. It is a std::vector-like type without the
resize-features, IIRC.

Matthias

>
> index1(0,0) = 0;
> index1(1,0) = 1;
>
> index2(0,0) = 0;
> index2(1,0) = 0;
>
> ublas::matrix_indirect<ublas::matrix<double, ublas::column_major>,
>     ublas::matrix<unsigned> > test(grid, index1, index2);
>
>
> Maybe there is an error already here.
>
> thanks, Marcel
>
>>
>> Marcel Rehberg wrote:
>>
>>> btw: Regarding the error for the matrix_indirect: For indexing I
>>> tried to
>>> use ublas::matrix<unsigned> but that got me several
>>>
>>> boost_1_44_0/boost/numeric/ublas/matrix_proxy.hpp:4381: error: no type
>>> named ?const_iterator? in ?class boost::numeric::ublas::matrix<unsigned
>>> int, boost::numeric::ublas::basic_row_major<unsigned int, int>,
>>> boost::numeric::ublas::unbounded_array<unsigned int,
>>> std::allocator<unsigned int> > >?
>>>
>>> and
>>>
>>> boost/numeric/ublas/matrix_proxy.hpp:4220: error: ?const class
>>> boost::numeric::ublas::matrix<unsigned int,
>>> boost::numeric::ublas::basic_row_major<unsigned int, int>,
>>> boost::numeric::ublas::unbounded_array<unsigned int,
>>> std::allocator<unsigned int> > >? has no member named ?preprocess?
>>
>>
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>> Sent to: Marcel.Rehberg_at_[hidden]
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