You should be able to do VecDuplicate() and then VecCopy() into the duplicate
but there may be a bug with the lock being passed through the VecDuplicate()
we'll check this and get back to your soon.
Barry
> On Aug 28, 2019, at 10:38 AM, Andrew Holm via petsc-users
> <[email protected]> wrote:
>
> Hello,
>
> We are working with an application using SNES and having a problem with the
> SNESFunction f called by SNESSetFunction(SNES snes,Vec r,PetscErrorCode
> (*f)(SNES,Vec,Vec,void*),void *ctx).
>
> We would like our SNESFunction(SNES snes,Vec x,Vec f,void *ctx) to be able to
> modify Vec x each time the function is called, how ever the vector is locked
> read only. We are running PETSc 3.9.3 with debugging turned on which tells us
> that Vec x is locked read only.
>
> To get around this, we have tried to make a local copy of the Vec x using
> VecCopy (x, xCopy). This gave us the error:
> [0]PETSC ERROR: Null argument, when expecting valid pointer
> [0]PETSC ERROR: Null Object: Parameter # 2
>
>
> We have also tried using VecDuplicate(vecWithDesiredLayout, &xLocalCopy) and
> then VecSetValues to fill the xLocalCopy with the values of Vec x. This gave
> the error:
> [0]PETSC ERROR: Object is in wrong state
> [0]PETSC ERROR: Vec is locked read only, argument # 2
>
>
> Also, we have tried using VecLockPop in PETSc 3.9.3 to overide the the lock
> however this seems gives a "Vector has been unlocked too many times" error at
> runtime:
> [0]PETSC ERROR: Object is in wrong state
> [0]PETSC ERROR: Vector has been unlocked too many times
>
>
> Any advice on how to make a local, modifiable copy of the locked read only
> vector? Any and All help is appreciated!
>
> Andy Holm
> Aeroscience Engineer
> Kratos Defense and Security Solutions
> 4904 Research Drive
> Huntsville, AL 35805
