table of contents
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/cgtcon.f(3) | Library Functions Manual | /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/cgtcon.f(3) |
NAME¶
/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/cgtcon.f
SYNOPSIS¶
Functions/Subroutines¶
subroutine CGTCON (norm, n, dl, d, du, du2, ipiv, anorm,
rcond, work, info)
CGTCON
Function/Subroutine Documentation¶
subroutine CGTCON (character norm, integer n, complex, dimension( * ) dl, complex, dimension( * ) d, complex, dimension( * ) du, complex, dimension( * ) du2, integer, dimension( * ) ipiv, real anorm, real rcond, complex, dimension( * ) work, integer info)¶
CGTCON
Purpose:
!> !> CGTCON estimates the reciprocal of the condition number of a complex !> tridiagonal matrix A using the LU factorization as computed by !> CGTTRF. !> !> An estimate is obtained for norm(inv(A)), and the reciprocal of the !> condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))). !>
Parameters
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. !>
N
!> N is INTEGER !> The order of the matrix A. N >= 0. !>
DL
!> DL is COMPLEX array, dimension (N-1) !> The (n-1) multipliers that define the matrix L from the !> LU factorization of A as computed by CGTTRF. !>
D
!> D is COMPLEX array, dimension (N) !> The n diagonal elements of the upper triangular matrix U from !> the LU factorization of A. !>
DU
!> DU is COMPLEX array, dimension (N-1) !> The (n-1) elements of the first superdiagonal of U. !>
DU2
!> DU2 is COMPLEX array, dimension (N-2) !> The (n-2) elements of the second superdiagonal of U. !>
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). IPIV(i) will always be either !> i or i+1; IPIV(i) = i indicates a row interchange was not !> required. !>
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. !>
RCOND
!> RCOND is REAL !> The reciprocal of the condition number of the matrix A, !> computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an !> estimate of the 1-norm of inv(A) computed in this routine. !>
WORK
!> WORK is COMPLEX array, dimension (2*N) !>
INFO
!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument had an illegal value !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 139 of file cgtcon.f.
Author¶
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Version 3.12.0 | LAPACK |