cgbcon.f (3)  Linux Manuals
NAME
cgbcon.f 
SYNOPSIS
Functions/Subroutines
subroutine cgbcon (NORM, N, KL, KU, AB, LDAB, IPIV, ANORM, RCOND, WORK, RWORK, INFO)
CGBCON
Function/Subroutine Documentation
subroutine cgbcon (characterNORM, integerN, integerKL, integerKU, complex, dimension( ldab, * )AB, integerLDAB, integer, dimension( * )IPIV, realANORM, realRCOND, complex, dimension( * )WORK, real, dimension( * )RWORK, integerINFO)
CGBCON
Purpose:

CGBCON estimates the reciprocal of the condition number of a complex general band matrix A, in either the 1norm or the infinitynorm, 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)) ).
Parameters:

NORM
NORM is CHARACTER*1 Specifies whether the 1norm condition number or the infinitynorm condition number is required: = '1' or 'O': 1norm; = 'I': Infinitynorm.
NN is INTEGER The order of the matrix A. N >= 0.
KLKL is INTEGER The number of subdiagonals within the band of A. KL >= 0.
KUKU is INTEGER The number of superdiagonals within the band of A. KU >= 0.
ABAB 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.
LDABLDAB is INTEGER The leading dimension of the array AB. LDAB >= 2*KL+KU+1.
IPIVIPIV is INTEGER array, dimension (N) The pivot indices; for 1 <= i <= N, row i of the matrix was interchanged with row IPIV(i).
ANORMANORM is REAL If NORM = '1' or 'O', the 1norm of the original matrix A. If NORM = 'I', the infinitynorm of the original matrix A.
RCONDRCOND is REAL The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(norm(A) * norm(inv(A))).
WORKWORK is COMPLEX array, dimension (2*N)
RWORKRWORK is REAL array, dimension (N)
INFOINFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value
Author:

Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
 November 2011
Definition at line 147 of file cgbcon.f.
Author
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