DSCond

Compute the condition number.

Synopsis

#include "slepcds.h" 
PetscErrorCode DSCond(DS ds,PetscReal *cond)

Logically Collective

Input Parameters

• ds - the direct solver context

• cond - the computed condition number

Notes

In standard eigenvalue problems, returns the inf-norm condition number of the first matrix, computed as cond(A) = norm(A)*norm(inv(A)).

In GSVD problems, returns the maximum of cond(A) and cond(B), where cond(.) is computed as the ratio of the largest and smallest singular values.

Does not take into account the extra row.

See Also

DSSolve(), DSSetExtraRow()

Level

advanced

Location

src/sys/classes/ds/interface/dsops.c

Implementations

DSCond_GSVD() in src/sys/classes/ds/impls/gsvd/dsgsvd.c
DSCond_HEP() in src/sys/classes/ds/impls/hep/dshep.c
DSCond_NHEP() in src/sys/classes/ds/impls/nhep/dsnhep.c

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