MatRestoreRow — PETSc 3.21.4 documentation

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# MatRestoreRow

Frees any temporary space allocated by `MatGetRow()`.

## Synopsis

    #include "petscmat.h"
    PetscErrorCode MatRestoreRow(Mat mat, PetscInt row, PetscInt *ncols, const PetscInt *cols[], const PetscScalar *vals[])

Not Collective

## Input Parameters

- mat - the matrix

- row - the row to get

- ncols - the number of nonzeros

- cols - the columns of the nonzeros

- vals - if nonzero the column values

## Notes

This routine should be called after you have finished examining the entries.

This routine zeros out `ncols`, `cols`, and `vals`. This is to prevent accidental us of the array after it has been restored. If you pass `NULL`, it will not zero the pointers. Use of `cols` or `vals` after `MatRestoreRow()` is invalid.

## Fortran Notes

The calling sequence is

       MatRestoreRow(matrix,row,ncols,cols,values,ierr)
          Mat     matrix (input)
          integer row    (input)
          integer ncols  (output)
          integer cols(maxcols) (output)
          double precision (or double complex) values(maxcols) output

Where maxcols >= maximum nonzeros in any row of the matrix.

In Fortran `MatRestoreRow()` MUST be called after `MatGetRow()` before another call to `MatGetRow()` can be made.

## See Also

Matrices, `Mat`, `MatGetRow()`

## Level

advanced

## Location

src/mat/interface/matrix.c

## Examples

src/mat/tutorials/ex12.c
src/mat/tutorials/ex16.c
src/ksp/ksp/tutorials/ex59.c

## Implementations

MatRestoreRow_MPIAdj() in src/mat/impls/adj/mpi/mpiadj.c
MatRestoreRow_MPIAIJ() in src/mat/impls/aij/mpi/mpiaij.c
MatRestoreRow_SeqAIJ() in src/mat/impls/aij/seq/aij.c
MatRestoreRow_MPIBAIJ() in src/mat/impls/baij/mpi/mpibaij.c
MatRestoreRow_SeqBAIJ() in src/mat/impls/baij/seq/baij.c
MatRestoreRow_ConstantDiagonal() in src/mat/impls/cdiagonal/cdiagonal.c
MatRestoreRow_MPIDense() in src/mat/impls/dense/mpi/mpidense.c
MatRestoreRow_SeqDense() in src/mat/impls/dense/seq/dense.c
MatRestoreRow_Diagonal() in src/mat/impls/diagonal/diagonal.c
MatRestoreRow_Htool() in src/mat/impls/htool/htool.cxx
MatRestoreRow_HYPRE() in src/mat/impls/hypre/mhypre.c
MatRestoreRow_SeqKAIJ() in src/mat/impls/kaij/kaij.c
MatRestoreRow_MPIKAIJ() in src/mat/impls/kaij/kaij.c
MatRestoreRow_MPISBAIJ() in src/mat/impls/sbaij/mpi/mpisbaij.c
MatRestoreRow_SeqSBAIJ() in src/mat/impls/sbaij/seq/sbaij.c
MatRestoreRow_SeqSELL() in src/mat/impls/sell/seq/sell.c

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Index of all manual pages