petsc-3.5.2 2014-09-08
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PCJACOBI

Jacobi (i.e. diagonal scaling preconditioning)

Options Database Key

-pc_jacobi_rowmax - use the maximum absolute value in each row as the scaling factor, rather than the diagonal
-pc_jacobi_rowsum - use the row sums as the scaling factor, rather than the diagonal
-pc_jacobi_abs - use the absolute value of the diagaonl entry

Notes: By using KSPSetPCSide(ksp,PC_SYMMETRIC) or -ksp_pc_side symmetric can scale each side of the matrix by the squareroot of the diagonal entries.

Zero entries along the diagonal are replaced with the value 1.0

See Also

PCCreate(), PCSetType(), PCType (for list of available types), PC,
PCJacobiSetUseRowMax(), PCJacobiSetUseRowSum(), PCJacobiSetUseAbs()

Level:beginner
Location:
src/ksp/pc/impls/jacobi/jacobi.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages

Examples

src/ksp/ksp/examples/tutorials/ex1.c.html
src/ksp/ksp/examples/tutorials/ex7.c.html
src/ksp/ksp/examples/tutorials/ex15.c.html
src/ksp/ksp/examples/tutorials/ex23.c.html
src/ksp/ksp/examples/tutorials/ex58.c.html
src/ksp/ksp/examples/tutorials/ex1f.F.html
src/ksp/ksp/examples/tutorials/ex2f.F.html
src/ksp/ksp/examples/tutorials/ex15f.F.html
src/ksp/ksp/examples/tutorials/ex21f.F.html
src/snes/examples/tutorials/ex74f.F90.html