---
name: "cla_gbrcond_c"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/cla_gbrcond_c.f"
---

# cla\_gbrcond\_c(3)

Part of [cla\_gbrcond\_c.f(3)](/cla_gbrcond_c.f/3.md).

## NAME

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

Univ. of Colorado Denver

NAG Ltd.

Definition at line **158** of file **cla\_gbrcond\_c.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.