MatCreateVecs#

Get vector(s) compatible with the matrix, i.e. with the same parallel layout, PetscLayout for rows and columns

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatCreateVecs(Mat mat, Vec *right, Vec *left)

Collective

Input Parameter#

mat - the matrix

Output Parameters#

right - (optional) vector that the matrix can be multiplied against
left - (optional) vector that the matrix vector product can be stored in

Options Database Key#

-mat_vec_type type - set the VecType of the created vectors during MatSetFromOptions()

Notes#

The blocksize of the returned vectors is determined by the row and column block sizes set with MatSetBlockSizes() or the single blocksize (same for both) set by MatSetBlockSize().

The VecType of the created vectors is determined by the MatType of mat. This can be overridden by using MatSetVecType() or the option -mat_vec_type.

These are new vectors which are not owned by the mat, they should be destroyed with VecDestroy() when no longer needed.

PETSc Vec always have all zero entries when created with MatCreateVecs() until routines such as VecSet() or VecSetValues() are used to change the values. There is no reason to call VecZeroEntries() after creation.