dolfin team mailing list archive

[N <tenpoundwalleye@xxxxxxxxx>]

----- Original Message ----
> From: A Navaei <axnavaei@xxxxxxxxxxxxxx>
> To: N <tenpoundwalleye@xxxxxxxxx>
> Cc: dolfin-dev@xxxxxxxxxx
> Sent: Monday, February 16, 2009 4:56:21 PM
> Subject: Re: [DOLFIN-dev] access to CSR data in python
> 
> 2009/2/16 N :
> >
> > Take a simple example like
> >
> > from dolfin import *
> > mesh = UnitSquare(4, 4)
> > V = FunctionSpace(mesh, "CG", 1)
> > v = TestFunction(V)
> > u = TrialFunction(V)
> > a = dot(grad(v), grad(u))*dx
> > A = assemble(a)
> >
> > The matrix A (with boost as the linear algebra base) gives the following for 
> attribute data:
> >    data(self) -> 
> std::tr1::tuple<(p.q(const).std::size_t,p.q(const).std::size_t,p.q(const).double,int)>
> >
> >    Return pointers to underlying compressed storage data. See
> >    GenericMatrix for documentation.
> >
> >
> > How can this be used to gain access to the column data, row pointer, and data 
> elements in the matrix?  I would like to have access to this data in Numpy 
> arrays without copying the data.  Is this possible?
> 
> A.array()  returns numpy.ndarray.
> 

This returns an ndarray for the dense matrix.  I'm looking for the CSR data.

Nate