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# KSPSetUpOnBlocks
Sets up the preconditioner for each block in the block Jacobi, block Gauss-Seidel, and overlapping Schwarz methods.
## Synopsis
```
#include "petscksp.h"
#include "petscmat.h"
PetscErrorCode KSPSetUpOnBlocks(KSP ksp)
```
Collective
## Input Parameter
- ***ksp -*** the `KSP` context
## Notes
`KSPSetUpOnBlocks()` is a routine that the user can optionally call for
more precise profiling (via -log_view) of the setup phase for these
block preconditioners. If the user does not call `KSPSetUpOnBlocks()`,
it will automatically be called from within `KSPSolve()`.
Calling `KSPSetUpOnBlocks()` is the same as calling `PCSetUpOnBlocks()`
on the PC context within the `KSP` context.
## See Also
[](ch_ksp), `PCSetUpOnBlocks()`, `KSPSetUp()`, `PCSetUp()`, `KSP`
## Level
advanced
## Location
src/ksp/ksp/interface/itfunc.c
## Examples
src/ksp/ksp/tutorials/ex10.c
src/ksp/ksp/tutorials/ex27.c
src/ksp/ksp/tutorials/ex72.c
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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/ksp/interface/itfunc.c)
[Index of all KSP routines](index.md)
[Table of Contents for all manual pages](/manualpages/index.md)
[Index of all manual pages](/manualpages/singleindex.md)