# cla_gbrcond_c.f - Man Page

SRC/cla_gbrcond_c.f

## Synopsis

### Functions/Subroutines

real function cla_gbrcond_c (trans, n, kl, ku, ab, ldab, afb, ldafb, ipiv, c, capply, info, work, rwork)
CLA_GBRCOND_C computes the infinity norm condition number of op(A)*inv(diag(c)) for general banded matrices.

## Function/Subroutine Documentation

### real function cla_gbrcond_c (character trans, integer n, integer kl, integer ku, complex, dimension( ldab, * ) ab, integer ldab, complex, dimension( ldafb, * ) afb, integer ldafb, integer, dimension( * ) ipiv, real, dimension( * ) c, logical capply, integer info, complex, dimension( * ) work, real, dimension( * ) rwork)

CLA_GBRCOND_C computes the infinity norm condition number of op(A)*inv(diag(c)) for general banded matrices.

Purpose:

CLA_GBRCOND_C Computes the infinity norm condition number of
op(A) * inv(diag(C)) where C is a REAL vector.
Parameters

TRANS

TRANS is 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

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

KL

KL is INTEGER
The number of subdiagonals within the band of A.  KL >= 0.

KU

KU is INTEGER
The number of superdiagonals within the band of A.  KU >= 0.

AB

AB is COMPLEX 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

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

AFB

AFB is COMPLEX array, dimension (LDAFB,N)
Details of the LU factorization of the band matrix A, as
computed by CGBTRF.  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

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

IPIV

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

C

C is REAL array, dimension (N)
The vector C in the formula op(A) * inv(diag(C)).

CAPPLY

CAPPLY is LOGICAL
If .TRUE. then access the vector C in the formula above.

INFO

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

WORK

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

RWORK

RWORK is REAL array, dimension (N).
Workspace.
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 158 of file cla_gbrcond_c.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page cla_gbrcond_c(3) is an alias of cla_gbrcond_c.f(3).

Tue Nov 28 2023 12:08:41 Version 3.12.0 LAPACK