petsc-3.9.4 2018-09-11
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MatDiagonalSet

 Computes Y = Y + D, where D is a diagonal matrix that is represented as a vector. Or Y[i,i] = D[i] if InsertMode is INSERT_VALUES.

Synopsis

#include "petscmat.h"  
PetscErrorCode  MatDiagonalSet(Mat Y,Vec D,InsertMode is)

Input Parameters

Y - the input matrix
D - the diagonal matrix, represented as a vector
i - INSERT_VALUES or ADD_VALUES

Neighbor-wise Collective on Mat and Vec

Notes: If the matrix Y is missing some diagonal entries this routine can be very slow. To make it fast one should initially fill the matrix so that all diagonal entries have a value (with a value of zero for those locations that would not have an entry).

Keywords

matrix, add, shift, diagonal

See Also

MatShift(), MatScale(), MatDiagonalScale()

Level

intermediate

Location

src/mat/utils/axpy.c

Examples

src/ts/examples/tutorials/ex50.c.html
src/tao/pde_constrained/examples/tutorials/elliptic.c.html

Implementations

MatDiagonalSet_MPIAIJ in src/mat/impls/aij/mpi/mpiaij.c
MatDiagonalSet_SeqAIJ in src/mat/impls/aij/seq/aij.c
MatDiagonalSet_IS in src/mat/impls/is/matis.c
MatDiagonalSet_MFFD in src/mat/impls/mffd/mffd.c
MatDiagonalSet_Nest in src/mat/impls/nest/matnest.c
MatDiagonalSet_MPISELL in src/mat/impls/sell/mpi/mpisell.c
MatDiagonalSet_Shell in src/mat/impls/shell/shell.c

Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages