MatGetColumnReductions#
Gets the reductions of each column of a sparse or dense matrix.
Synopsis#
#include "petscmat.h"
PetscErrorCode MatGetColumnReductions(Mat A, PetscInt type, PetscReal reductions[])
Input Parameters#
A - the matrix
type - A constant defined in
NormTypeorReductionType:NORM_2,NORM_1,NORM_INFINITY,REDUCTION_SUM_REALPART,REDUCTION_SUM_IMAGINARYPART,REDUCTION_MEAN_REALPART,REDUCTION_MEAN_IMAGINARYPART
Output Parameter#
reductions - an array as large as the TOTAL number of columns in the matrix
Note#
Each process has ALL the column reductions after the call. Because of the way this is computed each process gets all the values, if each process wants only some of the values it should extract the ones it wants from the array.
Developer Notes#
This routine is primarily intended as a back-end.
MatGetColumnNorms(), MatGetColumnSums(), and MatGetColumnMeans() are implemented using this routine.
See Also#
Matrices, Mat, ReductionType, NormType, MatGetColumnNorms(), MatGetColumnSums(), MatGetColumnMeans()
Level#
developer
Location#
Implementations#
MatGetColumnReductions_MPIAIJ() in src/mat/impls/aij/mpi/mpiaij.c
MatGetColumnReductions_SeqAIJ() in src/mat/impls/aij/seq/aij.c
MatGetColumnReductions_MPIBAIJ() in src/mat/impls/baij/mpi/mpibaij.c
MatGetColumnReductions_SeqBAIJ() in src/mat/impls/baij/seq/baij.c
MatGetColumnReductions_MPIDense() in src/mat/impls/dense/mpi/mpidense.c
MatGetColumnReductions_SeqDense() in src/mat/impls/dense/seq/dense.c
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