:orphan:
# VecSetPreallocationCOO
set preallocation for a vector using a coordinate format of the entries with global indices 
## Synopsis
```
#include "petscvec.h"   
PetscErrorCode VecSetPreallocationCOO(Vec x, PetscCount ncoo, const PetscInt coo_i[])
```
Collective


## Input Parameters

- ***x -*** vector being preallocated
- ***ncoo -*** number of entries
- ***coo_i -*** entry indices





## Notes
This and `VecSetValuesCOO()` provide an alernative API to using `VecSetValues()` to provide vector values.

This API is particularly efficient for use on GPUs.

Entries can be repeated, see `VecSetValuesCOO()`. Negative indices are not allowed unless vector option `VEC_IGNORE_NEGATIVE_INDICES` is set,
in which case they, along with the corresponding entries in `VecSetValuesCOO()`, are ignored. If vector option `VEC_NO_OFF_PROC_ENTRIES` is set,
remote entries are ignored, otherwise, they will be properly added or inserted to the vector.

The array coo_i[] may be freed immediately after calling this function.


## See Also
 [](ch_vectors), `Vec`, `VecSetValuesCOO()`, `VecSetPreallocationCOOLocal()`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/interface/vector.c.html#VecSetPreallocationCOO">src/vec/vec/interface/vector.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/mpi/kokkos/mpikok.kokkos.cxx.html#VecSetPreallocationCOO_MPIKokkos">VecSetPreallocationCOO_MPIKokkos in src/vec/vec/impls/mpi/kokkos/mpikok.kokkos.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/mpi/pdvec.c.html#VecSetPreallocationCOO_MPI">VecSetPreallocationCOO_MPI in src/vec/vec/impls/mpi/pdvec.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/seq/bvec2.c.html#VecSetPreallocationCOO_Seq">VecSetPreallocationCOO_Seq in src/vec/vec/impls/seq/bvec2.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/seq/kokkos/veckok.kokkos.cxx.html#VecSetPreallocationCOO_SeqKokkos">VecSetPreallocationCOO_SeqKokkos in src/vec/vec/impls/seq/kokkos/veckok.kokkos.cxx</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/vec/vec/interface/vector.c)


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