A breakdown in the Krylov method was detected so the method could not continue to enlarge the Krylov space. Could be due to a singular matrix or preconditioner. In KSPHPDDM, this is also returned when some search directions within a block are colinear. Level: beginner

See Also

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