Provided by: liblapack-doc_3.3.1-1_all

#### NAME

```       LAPACK-3  -  ZLA_GBRCOND_X  Compute the infinity norm condition number of  op(A) * diag(X)
where X is a COMPLEX*16 vector

```

#### SYNOPSIS

```       DOUBLE PRECISION FUNCTION ZLA_GBRCOND_X( TRANS, N, KL, KU, AB, LDAB, AFB, LDAFB, IPIV,  X,
INFO, WORK, RWORK )

IMPLICIT     NONE

CHARACTER    TRANS

INTEGER      N, KL, KU, KD, KE, LDAB, LDAFB, INFO

INTEGER      IPIV( * )

COMPLEX*16   AB( LDAB, * ), AFB( LDAFB, * ), WORK( * ), X( * )

DOUBLE       PRECISION RWORK( * )

```

#### PURPOSE

```          ZLA_GBRCOND_X Computes the infinity norm condition number of
op(A) * diag(X) where X is a COMPLEX*16 vector.

```

#### ARGUMENTS

```        TRANS   (input) CHARACTER*1
Specifies the form of the system of equations:
= 'N':  A * X = B     (No transpose)
= 'T':  A**T * X = B  (Transpose)
= 'C':  A**H * X = B  (Conjugate Transpose = Transpose)

N       (input) INTEGER
The number of linear equations, i.e., the order of the
matrix A.  N >= 0.

KL      (input) INTEGER
The number of subdiagonals within the band of A.  KL >= 0.

KU      (input) INTEGER
The number of superdiagonals within the band of A.  KU >= 0.

AB      (input) COMPLEX*16 array, dimension (LDAB,N)
On entry, the matrix A in band storage, in rows 1 to KL+KU+1.
The j-th column of A is stored in the j-th column of the
array AB as follows:
AB(KU+1+i-j,j) = A(i,j) for max(1,j-KU)<=i<=min(N,j+kl)

LDAB    (input) INTEGER
The leading dimension of the array AB.  LDAB >= KL+KU+1.

AFB     (input) COMPLEX*16 array, dimension (LDAFB,N)
Details of the LU factorization of the band matrix A, as
computed by ZGBTRF.  U is stored as an upper triangular
band matrix with KL+KU superdiagonals in rows 1 to KL+KU+1,
and the multipliers used during the factorization are stored
in rows KL+KU+2 to 2*KL+KU+1.

LDAFB   (input) INTEGER
The leading dimension of the array AFB.  LDAFB >= 2*KL+KU+1.

IPIV    (input) INTEGER array, dimension (N)
The pivot indices from the factorization A = P*L*U
as computed by ZGBTRF; row i of the matrix was interchanged
with row IPIV(i).

X       (input) COMPLEX*16 array, dimension (N)
The vector X in the formula op(A) * diag(X).

INFO    (output) INTEGER
= 0:  Successful exit.
i > 0:  The ith argument is invalid.

WORK    (input) COMPLEX*16 array, dimension (2*N).
Workspace.

RWORK   (input) DOUBLE PRECISION array, dimension (N).
Workspace.

LAPACK routine (version 3.2.1)          April 2011                     ZLA_GBRCOND_X(3lapack)
```