# KSP_DIVERGED_INDEFINITE_PC

It appears the preconditioner is indefinite (has both positive and negative eigenvalues) and this Krylov method (KSPCG) requires it to be positive definite

Notes: This can happen with the PCICC preconditioner, use -pc_icc_shift to force the PCICC preconditioner to generate a positive definite preconditioner

### See Also

KSPSolve(), KSPGetConvergedReason(), KSPConvergedReason, KSPSetTolerances()

Level:beginner
Location:src/ksp/ksp/../../../include/petscksp.h
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages

### Examples

src/ksp/pc/examples/tutorials/ex1.c.html
src/ksp/pc/examples/tutorials/ex2.c.html