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LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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| subroutine cgbcon | ( | character | NORM, |
| integer | N, | ||
| integer | KL, | ||
| integer | KU, | ||
| complex, dimension( ldab, * ) | AB, | ||
| integer | LDAB, | ||
| integer, dimension( * ) | IPIV, | ||
| real | ANORM, | ||
| real | RCOND, | ||
| complex, dimension( * ) | WORK, | ||
| real, dimension( * ) | RWORK, | ||
| integer | INFO | ||
| ) |
CGBCON
Download CGBCON + dependencies [TGZ] [ZIP] [TXT]
CGBCON estimates the reciprocal of the condition number of a complex
general band matrix A, in either the 1-norm or the infinity-norm,
using the LU factorization computed by CGBTRF.
An estimate is obtained for norm(inv(A)), and the reciprocal of the
condition number is computed as
RCOND = 1 / ( norm(A) * norm(inv(A)) ). | [in] | NORM | NORM is CHARACTER*1
Specifies whether the 1-norm condition number or the
infinity-norm condition number is required:
= '1' or 'O': 1-norm;
= 'I': Infinity-norm. |
| [in] | N | N is INTEGER
The order of the matrix A. N >= 0. |
| [in] | KL | KL is INTEGER
The number of subdiagonals within the band of A. KL >= 0. |
| [in] | KU | KU is INTEGER
The number of superdiagonals within the band of A. KU >= 0. |
| [in] | AB | AB is COMPLEX array, dimension (LDAB,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. |
| [in] | LDAB | LDAB is INTEGER
The leading dimension of the array AB. LDAB >= 2*KL+KU+1. |
| [in] | IPIV | IPIV is INTEGER array, dimension (N)
The pivot indices; for 1 <= i <= N, row i of the matrix was
interchanged with row IPIV(i). |
| [in] | ANORM | ANORM is REAL
If NORM = '1' or 'O', the 1-norm of the original matrix A.
If NORM = 'I', the infinity-norm of the original matrix A. |
| [out] | RCOND | RCOND is REAL
The reciprocal of the condition number of the matrix A,
computed as RCOND = 1/(norm(A) * norm(inv(A))). |
| [out] | WORK | WORK is COMPLEX array, dimension (2*N) |
| [out] | RWORK | RWORK is REAL array, dimension (N) |
| [out] | INFO | INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value |
1.9.4