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<TITLE>Nonlinear solvers - SNES</TITLE>
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<H2> Nonlinear solvers - SNES: <A HREF="PETSC_DIRsrc/snes/examples/tutorials/index.html">Examples</A></H2>

The Scalable Nonlinear Equations Solvers (SNES) component provides an
easy-to-use interface to Newton-type, quasi-Newton, full approximation scheme (FAS) multigrid, and other methods for solving systems of
nonlinear equations.  SNES users can set various algorithmic options
at runtime via the options database (e.g., specifying a trust region
method via
<font face ="Courier">
-snes_type tr
</font face>
).  

SNES internally employs <A HREF="PETSC_DIRdocs/manualpages/KSP/index.html">KSP</A> for the solution of 
its linear systems.
SNES users can also set KSP options directly in application
codes by first extracting the KSP context from the SNES context via
<A HREF="PETSC_DIRdocs/manualpages/SNES/SNESGetKSP.html">SNESGetKSP()</A>
and then directly calling various KSP (and PC) routines (e.g., 
<A HREF="PETSC_DIRdocs/manualpages/PC/PCSetType.html">PCSetType()</A>
).

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