Dear all,
I'm solving a system using petsc and I get a global Vec, say X . It uses
DMDA with 4 dofs (3 velocity + 1 pressure). X contains velocity at the cell
faces since I solve using staggered grid.
Now I'd like to create one array for velocity with values at cell centers
and another array for pressure (not the Vec so that I can send the pointer
to the array to other part of the code that does not use Petsc).
Currently what I do is :
------ Vec X, X_local;
------ PetscScalar *X_array;
// Scatter X to X_local and then use:
------- VecGetArray(X_local, &X_array)
And then have a function, say
getVelocityAt(x, y, z, component) {
// interpolate velocity at (x,y,z) cell center using X_array
}
The function getVelocityAt() gets called from outside petsc in a loop over
all (x,y,z) positions.
This is not done in parallel.
Now, how do I use Petsc to instead interpolate the cell center velocities
in parallel and store it
in an array say
PetscScalar *X_array_cellCenter;
?
This would need to have size one less along each axis compared to the
orginal DMDA size.
This way I intend to return X_array_cellCenter to the code outside Petsc.
