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Re: [Bug 594954] Re: uBLAS GMRES solver fails on first run

 

On Tue, Jun 29, 2010 at 11:50:38AM +0200, Mehdi wrote:
> Is there any specific reason why we have this type of problems in
> resizing uBLAS vectors not other type of vectors?

Yes, because of a bug in the uBLAS resize function (it does not
initialize data).

> Note that resizing a vector becomes important in the adaptive methods.
> Since when a function updates, we need to resize its underlying vector.
> If we clear a vector, then we lose all data that we had there.

There's no point in keeping the old dofs as part of the vector since
the number of the mesh (and the old dofs) may change. What is needed
for adaptive methods is to interpolate the old solution to the new
mesh (which is already implemented in DOLFIN).

--
Anders


> Mehdi
>
> On Mon, 2010-06-28 at 15:01 +0000, Anders Logg wrote:
> > The problem was that x = Vector(b.size()) created a vector which
> > sometimes contained strange numbers. This has been changed now (in
> > uBLASVector::resize()) so that the vector is always zero. Took me a
> > while to work through all the 29 different axpy_prod that call each
> > other in operation.hpp in uBLAS...
> >
> > Should be fixed now.
> >
> > ** Changed in: dolfin
> >        Status: Confirmed => Fix Committed
> >
>
>
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