dolfin team mailing list archive

["Garth N. Wells" <g.n.wells@xxxxxxxxxx>]

Anders Logg wrote:
> In GenericMatrix, we have the following functions in addition to the
> GenericTensor interface (not counting the virtual functions add, get,
> set that are specializations of the corresponding functions in
> GenericTensor):
>
>   /// Initialize M x N matrix with given maximum number of nonzeros in each row
>   virtual void init(uint M, uint N, uint nzmax) = 0;
>     
>   /// Initialize M x N matrix with given number of nonzeros per row
>   virtual void init(uint M, uint N, const uint nz[]) = 0;
>
>   /// Set all entries to zero
>   virtual void zero() = 0;
>
>   /// Set given rows to identity matrix
>   virtual void ident(const uint rows[], uint m) = 0;
>
> Since we have init(SparsityPattern), it looks to me like the first two
> could be removed.

We should design SparsityPattern such that it doesn't necessarily 
contain the full layout, but perhaps just the maximum number of 
non-zeroes. init(SparsityPattern sparsity_pattern) should then 
initialise a matrix the best way it can with what information 
sparsity_pattern has.

> How about zero() and ident(), do we need them for assembly?
>
> We could say that init() should zero out the matrix and use set()
> instead of ident(). Or perhaps we should stick to ident() so we can
> map it to MatZeroRowsIS(A, is, one) in PETSc?

We should stick with ident() and use the PETsc function for this.

Ideally, init() will take an argument indicating whether or not the 
matrix structure has changed,

  init(const SparsityPattern& sparsity_pattern, bool reset = true);

and reset the layout by default. If reset == false, then init() should 
just zero the matrix and the function zero() can be removed.

Garth



> /Anders
>
>
> On Mon, Apr 16, 2007 at 01:37:15PM +0200, DOLFIN wrote:
> > One or more new changesets pushed to the primary DOLFIN repository.
> > A short summary of the last three changesets is included below.
> >
> > changeset:   2849:25bd777364d1b8bcc1ac36e39089b653d39bf075
> > tag:         tip
> > user:        "Garth N. Wells <g.n.wells@xxxxxxxxxx>"
> > date:        Mon Apr 16 13:37:02 2007 +0200
> > files:       configure configure.ac src/kernel/la/dolfin/GenericMatrix.h src/kernel/la/dolfin/uBlasMatrix.h
> > description:
> > Fix configure and remove some functions from GenericMatrix.
> >
> >
> > changeset:   2848:42b0e2f7e1698615393798e1f540918d4e571ea9
> > parent:      2847:6ffac525dc2e8beee3250f45f4da369927b51734
> > parent:      2846:c7d5e0ce18f10fbff31fb5fa200b61cca062582a
> > user:        "Garth N. Wells <g.n.wells@xxxxxxxxxx>"
> > date:        Mon Apr 16 12:53:09 2007 +0200
> > files:       
> > description:
> > merge
> >
> >
> > changeset:   2847:6ffac525dc2e8beee3250f45f4da369927b51734
> > parent:      2844:695032c059f4aed5ee4a2da71ae295607491fa9b
> > user:        "Garth N. Wells <g.n.wells@xxxxxxxxxx>"
> > date:        Mon Apr 16 12:52:17 2007 +0200
> > files:       src/kernel/io/VTKFile.cpp
> > description:
> > Small changes in VTKFile.
> >
> >
> > ----------------------------------------------------------------------
> > For more details, visit http://www.fenics.org/hg/dolfin
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