| [eigen] adding constructor to SparseMatrix |
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- To: eigen <eigen@xxxxxxxxxxxxxxxxxxx>
- Subject: [eigen] adding constructor to SparseMatrix
- From: Daniel Lowengrub <lowdanie@xxxxxxxxx>
- Date: Mon, 7 Jun 2010 01:11:28 +0300
- Cc: Gael Guennebaud <gael.guennebaud@xxxxxxxxx>
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Sorry about the previous mis-post.
I think that it'd be useful to be able to quickly cast a regular
Matrix type into a SparseMatrix. I have two questions about the
implementation:
1) Would it be better to implement a new SparseMatrix ctor that
accepts a Matrix as an argument, or to implement a function like
sparseView in the Matrix class which returns a SparseMatrix?
2) At what level would it make sense for this to work? In the first
direction, a general MatrixBase shouldn't be able to be turned into a
SparseMatrix because this doesn't make sense for some subtypes of
MatrixBases such as expressions. In the other direction, if the
answer to the first question is to add a ctor, then should it be added
to SparseMatrixBase and be available to all of it's children, or
should it be specific to SparseMatrix? Casting a DenseMatrix to a
SparseMatrix is probably most useful when a DenseMatrix is constructed
as part of an algorithm but the algorithm requires operations like
factorization and linear system solving which are more efficient when
performed on a SparseMatrix [if the matrix is truly sparse]. Because
of this, casting a Matrix to a DynamicSparseMatrix doesn't seem too
helpful.
What do you think?
Daniel
On 6/7/10, Daniel Lowengrub <lowdanie@xxxxxxxxx> wrote:
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