[petsc-users] questions

[Ethan Coon]

On Thu, 2011-11-17 at 13:35 -0600, xiaohl wrote:
> Hi Mike
> 
>  I created the binary file from a ASCII file by C.
>  How could I create a file which I could use for petsc with DM routine?
> 

There are a few ways to do this, but the easiest options are -- 

1. write a C program that creates a DM and a Vec, sets the values of the
Vec, and calls VecView (like the example you quoted does).  

2. use matlab or python/numpy to generate arrays of the correct
size/type/order, and then save those arrays to Petsc Binary format using
the scripts in $PETSC_DIR/bin/matlab and $PETSC_DIR/bin/pythonscripts


Ethan

>  Hailong
> 
>  On Wed, 2 Nov 2011 15:53:27 -0500, Barry Smith <bsmith at mcs.anl.gov> 
>  wrote:
> > On Nov 2, 2011, at 3:42 PM, Matthew Knepley wrote:
> >
> >> On Wed, Nov 2, 2011 at 8:38 PM, xiaohl <xiaohl at ices.utexas.edu> 
> >> wrote:
> >> Hi
> >>
> >> I am going to implement cell center difference method for
> >> u = - K grad p
> >> div u = f
> >> where p is the pressure , u is the velocity, f is the source term.
> >>
> >> my goal is to assemble the matrix and test the performance of 
> >> different linear solvers in parallel.
> >>
> >> my question is how can I read the input file for K where K is n*n 
> >> tensor.
> >>
> >> MatLoad()
> >
> >    Hm, I think you should use a DMDA with n*n size dof and then use
> > VecLoad() to load the entries of K.
> >
> >    Barry
> >
> >>
> >> second one is that do you have any similar examples?
> >>
> >> Nothing with the mixed-discretization of the Laplacian.
> >>
> >>    Matt
> >>
> >> Hailong
> >>
> >>
> >>
> >> --
> >> What most experimenters take for granted before they begin their 
> >> experiments is infinitely more interesting than any results to which 
> >> their experiments lead.
> >> -- Norbert Wiener
> 

-- 
------------------------------------
Ethan Coon
Post-Doctoral Researcher
Applied Mathematics - T-5
Los Alamos National Laboratory
505-665-8289

http://www.ldeo.columbia.edu/~ecoon/
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