| Re: [eigen] How to create a Matrix<...> without copying data ? |
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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] How to create a Matrix<...> without copying data ?
- From: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
- Date: Mon, 17 May 2010 06:30:02 -0400
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You can do:
PartialPivLU<MatrixXd> lu(matrix.block(...));
or, from your double* pointer,
PartialPivLU<MatrixXd>
lu(Map<MatrixXd>(pointer,rows,cols).block(...));
or you can even get rid of the block() call by doing a strided Map.
What we don't allow at the moment is in-place LU, i.e. allowing to not
even copy that block.
Benoit
2010/5/17 <vincent.lejeune@xxxxxxxxxx>:
>
> Hi,
>
>
>
> I have a matrix stored as a double* in columnsmajor format.
>
> I would like to compute the LU factorisation of a part of the matrix (that
>
> is, not the whole matrix, just a sub square of it) inplace, ie I do not
>
> want to copy data to an temporary buffer.
>
>
>
> Is it possible using Eigen ? I saw that PartialPivLU class copy input
>
> matrix when constructed...
>
>
>
> Thx,
>
> Vincent
>
>
>