# Linear Solvers and Krylov Methods (KSP) The `KSP` class provides an easy-to-use interface to the combination of a Krylov subspace iterative method and a preconditioner `PC` for the solution of linear systems and some least squares problems. See `PETSCREGRESSORLINEAR` for additional regression (least squares) solvers. Examples

Source files

bddcnullspace.c
bddc.c
bddcfetidp.c
bddcgraph.c
bddcprivate.c
bddcscalingbasic.c
bddcschurs.c