KSPCGTRNormType

Norm used for the trust-region constraint in KSPCG, KSPSTCG, KSPNASH, and KSPGLTR

Synopsis

typedef enum {
  KSP_CG_TR_NORM_PRECONDITIONED,
  KSP_CG_TR_NORM_UNPRECONDITIONED
} KSPCGTRNormType;

Values

• KSP_CG_TR_NORM_PRECONDITIONED - use \(\sqrt{x^H M x}\), where the preconditioner applies \(M^{-1}\)

• KSP_CG_TR_NORM_UNPRECONDITIONED - use the Euclidean norm \(\sqrt{x^H x}\) (default)

Note

These norms measure the solution vector \(x\). The residual norm used for convergence is selected independently with KSPSetNormType().

See Also

KSP: Linear System Solvers, KSP, KSPCGSetTRNormType(), KSPCGGetTRNormType(), KSPCGGetTRSolutionNorm(), KSPCGSetRadius(), KSPNormType

Level

advanced

Location

include/petscksp.h

Examples

src/ksp/ksp/tests/ex94.c

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Index of all KSP routines
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