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 \(\infty\)-norm condition number of the first matrix, computed as \(\kappa_\infty(A) = \|A\|_\infty\|A^{-1}\|_\infty\).

In GSVD problems, returns the maximum of \(\kappa_2(A)\) and \(\kappa_2(B)\), where \(\kappa_2(\cdot)\) is computed as the ratio of the largest and smallest singular values.

Does not take into account the extra row.