VecLockWriteSet#

Lock or unlock a vector for exclusive read/write access

Synopsis#

#include "petscvec.h"   
PetscErrorCode VecLockWriteSet(Vec x, PetscBool flg)

Logically Collective

Input Parameters#

  • x - the vector

  • flg - PETSC_TRUE to lock the vector for exclusive read/write access; PETSC_FALSE to unlock it.

Notes#

The function is useful in split-phase computations, which usually have a begin phase and an end phase. One can call VecLockWriteSet(x,PETSC_TRUE) in the begin phase to lock a vector for exclusive access, and call VecLockWriteSet(x,PETSC_FALSE) in the end phase to unlock the vector from exclusive access. In this way, one is ensured no other operations can access the vector in between. The code may like

       VecGetArray(x,&xdata); // begin phase
       VecLockWriteSet(v,PETSC_TRUE);

       Other operations, which can not access x anymore (they can access xdata, of course)

       VecRestoreArray(x,&vdata); // end phase
       VecLockWriteSet(v,PETSC_FALSE);

The call can not be nested on the same vector, in other words, one can not call VecLockWriteSet(x,PETSC_TRUE) again before calling VecLockWriteSet(v,PETSC_FALSE).

See Also#

Vectors and Parallel Data, Vec, VecRestoreArray(), VecGetArrayRead(), VecLockReadPush(), VecLockReadPop(), VecLockGet()

Level#

intermediate

Location#

src/vec/vec/interface/rvector.c

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