---
name: "dla_gbrcond"
section: "3lapack"
platform: "linux"
package: "liblapack-doc"
version: "3.2.1-8"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/dla_gbrcond/3lapack"
---

# dla\_gbrcond(3lapack)

DLA\_GERCOND Estimate the Skeel condition number of op(A) \* op2(C) where op2 is determined by CMODE as follows CMODE = 1 op2(C) = C CMODE = 0 op2(C) = I CMODE = -1 op2(C) = inv(C) The Skeel condition number cond(A) = norminf( \|inv(A)\|\|A\| ) is computed by computing scaling factors R such that diag(R)\*A\*op2(C) is row equilibrated and computing the standard infinity-norm condition number

## NAME

DLA\_GBRCOND - DLA\_GERCOND Estimate the Skeel condition number of op(A) \* op2(C)  where op2 is determined by CMODE as follows  CMODE = 1 op2(C) = C  CMODE = 0 op2(C) = I  CMODE = -1 op2(C) = inv(C)  The Skeel condition number cond(A) = norminf( \|inv(A)\|\|A\| )  is computed by computing scaling factors R such that  diag(R)\*A\*op2(C) is row equilibrated and computing the standard  infinity-norm condition number

## SYNOPSIS

- DOUBLE PRECISION

  FUNCTION DLA\_GBRCOND( TRANS, N, KL, KU, AB, LDAB, AFB, LDAFB, IPIV, CMODE, C, INFO, WORK, IWORK )

- IMPLICIT

  NONE

- CHARACTER

  TRANS

- INTEGER

  N, LDAB, LDAFB, INFO, KL, KU, CMODE

- INTEGER

  IWORK( \* ), IPIV( \* )

- DOUBLE

  PRECISION AB( LDAB, \* ), AFB( LDAFB, \* ), WORK( \* ), C( \* )

## PURPOSE

   DLA\_GERCOND Estimates the Skeel condition number of  op(A) \* op2(C)\
    where op2 is determined by CMODE as follows\
    CMODE =  1    op2(C) = C\
    CMODE =  0    op2(C) = I\
    CMODE = -1    op2(C) = inv(C)\
    The Skeel condition number  cond(A) = norminf( \|inv(A)\|\|A\| )\
    is computed by computing scaling factors R such that\
    diag(R)\*A\*op2(C) is row equilibrated and computing the standard\
    infinity-norm condition number.

## ARGUMENTS

- WORK double precision workspace of size 5\*N.

  - IWORK integer workspace of size N.