[petsc-users] Inquiry about the PetscScalar in Petsc.

[neil liu]

Thanks for your reply.
I am using DMPLEX to read GMSH. And it seems I have to use
DMGetCoordinatesLocal();
VecGetArray(veccords, &coords);//it seems coords has to be defined by
complex either.

2) Store the coordinates in coords with imaginary part equal to zero.
I got the coordinates from above function *VecGetArray*, therefore will
this reduce the memory?

3) is a good way to work around that.


On Tue, Jul 11, 2023 at 11:40 AM Barry Smith <bsmith at petsc.dev> wrote:

>
>   Not really. PetscScalar (and entries of vectors etc) are either real or
> complex, they cannot be mixed.
>
>   What parts of PETSc are you using, DM?
>
>   You can
>
> 1) store the coordinates in arrays and not use Vec for them. (of if you
> are not using DM)
> 2) sore them in Vec but with imaginary part 0
> 3) rewrite your complex systems as real systems (with twice as many
> unknowns, but only real ones)
>
>   Barry
>
>
> > On Jul 11, 2023, at 11:34 AM, neil liu <liufield at gmail.com> wrote:
> >
> > Dear Petsc developers,
> >
> > My computation involves both real and complex numbers.
> > For example, my coordinate is real, but my matrix is complex.
> >
> > I use VecGetArray to get the coordinates. But it seems coordinates have
> to be defined in a complex manner to be consistent with complex matrix.
> >
> > Is there some ways to work around this if I understood correctly ?
> >
> > Thanks,
> >
> > Xiaodong
> >
> >
> >
>
>
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