MatShift#
Computes Y = Y + a I, where a is a PetscScalar
Synopsis#
#include "petscmat.h"
PetscErrorCode MatShift(Mat Y, PetscScalar a)
Neighbor-wise Collective
Input Parameters#
Y - the matrix
a - the
PetscScalar
Notes#
If Y is a rectangular matrix, the shift is done on the main diagonal of the matrix (https://en.wikipedia.org/wiki/Main_diagonal)
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). No operation is performed when a is zero.
To form Y = Y + diag(V) use MatDiagonalSet()
See Also#
Matrices, Mat, MatDiagonalSet(), MatScale(), MatDiagonalScale()
Level#
intermediate
Location#
Examples#
src/ksp/ksp/tutorials/ex1.c
src/ksp/ksp/tutorials/ex27.c
src/ksp/ksp/tutorials/ex79.c
src/ksp/ksp/tutorials/ex81.c
src/ksp/ksp/tutorials/ex82.c
src/snes/tutorials/ex20.c
src/tao/constrained/tutorials/tomographyADMM.c
src/tao/pde_constrained/tutorials/hyperbolic.c
src/tao/pde_constrained/tutorials/parabolic.c
src/tao/tutorials/ex4.c
src/ts/tutorials/ex16fwd.c
Implementations#
MatShift_MPIAIJ in src/mat/impls/aij/mpi/mpiaij.c
MatShift_SeqAIJ in src/mat/impls/aij/seq/aij.c
MatShift_MPIBAIJ in src/mat/impls/baij/mpi/mpibaij.c
MatShift_SeqBAIJ in src/mat/impls/baij/seq/baij.c
MatShift_ConstantDiagonal in src/mat/impls/cdiagonal/cdiagonal.c
MatShift_MPIDense in src/mat/impls/dense/mpi/mpidense.c
MatShift_SeqDense in src/mat/impls/dense/seq/dense.c
MatShift_IS in src/mat/impls/is/matis.c
MatShift_Nest in src/mat/impls/nest/matnest.c
MatShift_MPISBAIJ in src/mat/impls/sbaij/mpi/mpisbaij.c
MatShift_SeqSBAIJ in src/mat/impls/sbaij/seq/sbaij.c
MatShift_ScaLAPACK in src/mat/impls/scalapack/matscalapack.c
MatShift_MPISELL in src/mat/impls/sell/mpi/mpisell.c
MatShift_SeqSELL in src/mat/impls/sell/seq/sell.c
MatShift_Shell in src/mat/impls/shell/shell.c
MatShift_SubMatrix in src/mat/impls/submat/submat.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages