You should also not call PetscInitialize() from within your user MatMult
function.
On Fri, 7 Apr 2017 at 13:24, Matthew Knepley wrote:
> On Fri, Apr 7, 2017 at 5:11 AM, Francesco Migliorini <
> francescomigliorin...@gmail.com> wrote:
>
> Hello,
>
> I need to solve a linear system using GMRES
On Fri, Apr 7, 2017 at 5:11 AM, Francesco Migliorini <
francescomigliorin...@gmail.com> wrote:
> Hello,
>
> I need to solve a linear system using GMRES without creating explicitly
> the matrix because very large. So, I am trying to use the MatShell strategy
> but I am stucked. The problem is that
Hello,
I need to solve a linear system using GMRES without creating explicitly the
matrix because very large. So, I am trying to use the MatShell strategy but
I am stucked. The problem is that it seems to me that inside the
user-defined MyMatMult it is required to use MatMult and this would
honest