petsc-3.14.5 2021-03-03
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# MatGetRowMaxAbs

Gets the maximum value (in absolute value) of each row of the matrix

### Synopsis

    #include "petscmat.h"
    PetscErrorCode MatGetRowMaxAbs(Mat mat,Vec v,PetscInt idx[])

Logically Collective on Mat

### Input Parameters

| mat | - the matrix

### Output Parameter

| v | - the vector for storing the maximums
| idx | - the indices of the column found for each row (or NULL if not needed)

### Notes

if a row is completely empty or has only 0.0 values then the idx[] value for that row is 0 (the first column).

This code is only implemented for a couple of matrix formats.

### See Also

MatGetDiagonal(), MatCreateSubMatrices(), MatCreateSubMatrix(), MatGetRowMax(), MatGetRowMin()

### Level

intermediate

### Location

src/mat/interface/matrix.c

### Examples

src/ksp/ksp/tutorials/ex72.c.html

### Implementations

MatGetRowMaxAbs_MPIAIJ in src/mat/impls/aij/mpi/mpiaij.c
MatGetRowMaxAbs_SeqAIJ in src/mat/impls/aij/seq/aij.c
MatGetRowMaxAbs_MPIBAIJ in src/mat/impls/baij/mpi/mpibaij.c
MatGetRowMaxAbs_SeqBAIJ in src/mat/impls/baij/seq/baij.c
MatGetRowMaxAbs_SeqDense in src/mat/impls/dense/seq/dense.c
MatGetRowMaxAbs_MPISBAIJ in src/mat/impls/sbaij/mpi/mpisbaij.c
MatGetRowMaxAbs_SeqSBAIJ in src/mat/impls/sbaij/seq/sbaij2.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages