| Re: [eigen] const Static Vector/Matrix howto |
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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] const Static Vector/Matrix howto
- From: Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>
- Date: Thu, 4 Feb 2010 15:55:15 +0100
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I think you can do this:
EIGEN_ALIGN16 double matrix_data[] = { 1., 2., 3. ,4. };
Matrix2d::AlignedMapType m(matrix_data);
There are no copies involved and the matrix m is aligned.
- Hauke
On Thu, Feb 4, 2010 at 3:40 PM, Thomas Capricelli <orzel@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> I'd like to ask about a problem i often encounter. I need to allocate a static const Vector or matrix. That is, i already know the coefficients.
>
> I currently do something like this:
>
> static double matrix_data[] = { 1., 2., 3. ,4. };
> static Eigen::Matrix< double, 2, 2 > m(matrix_data);
>
> Which is far from perfect because i guess the data is copied, so we have both an allocation and a copy that are not really needed.
>
> I thought about using ::map:
>
> Map<Eigen::Matrix< double, 2, 2 > > m(matrix_data);
>
> but i'm not sure how efficient this is.. i guess in my first try the constructor of ::Matrix ensure alignement while in the second case, the data is where matrix_data is, which has no guaranty of being aligned, is it ?
>
> So what would you suggest ? Should i ensure (how?) that matrix_data is aligned and use the Map stuff ? Any other idea?
>
> ++
> Thomas
> --
> Thomas Capricelli <orzel@xxxxxxxxxxxxxxx>
> http://www.freehackers.org/thomas
>
>
>