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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dtbcon.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dtbcon.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dtbcon.f

SYNOPSIS

Functions/Subroutines


subroutine DTBCON (norm, uplo, diag, n, kd, ab, ldab, rcond, work, iwork, info)
DTBCON

Function/Subroutine Documentation

subroutine DTBCON (character norm, character uplo, character diag, integer n, integer kd, double precision, dimension( ldab, * ) ab, integer ldab, double precision rcond, double precision, dimension( * ) work, integer, dimension( * ) iwork, integer info)

DTBCON

Purpose:

!>
!> DTBCON estimates the reciprocal of the condition number of a
!> triangular band matrix A, in either the 1-norm or the infinity-norm.
!>
!> The norm of A is computed and an estimate is obtained for
!> norm(inv(A)), then 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 1-norm condition number or the
!>          infinity-norm condition number is required:
!>          = '1' or 'O':  1-norm;
!>          = 'I':         Infinity-norm.
!> 

UPLO

!>          UPLO is CHARACTER*1
!>          = 'U':  A is upper triangular;
!>          = 'L':  A is lower triangular.
!> 

DIAG

!>          DIAG is CHARACTER*1
!>          = 'N':  A is non-unit triangular;
!>          = 'U':  A is unit triangular.
!> 

N

!>          N is INTEGER
!>          The order of the matrix A.  N >= 0.
!> 

KD

!>          KD is INTEGER
!>          The number of superdiagonals or subdiagonals of the
!>          triangular band matrix A.  KD >= 0.
!> 

AB

!>          AB is DOUBLE PRECISION array, dimension (LDAB,N)
!>          The upper or lower triangular band matrix A, stored in the
!>          first kd+1 rows of the array. The j-th column of A is stored
!>          in the j-th column of the array AB as follows:
!>          if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j;
!>          if UPLO = 'L', AB(1+i-j,j)    = A(i,j) for j<=i<=min(n,j+kd).
!>          If DIAG = 'U', the diagonal elements of A are not referenced
!>          and are assumed to be 1.
!> 

LDAB

!>          LDAB is INTEGER
!>          The leading dimension of the array AB.  LDAB >= KD+1.
!> 

RCOND

!>          RCOND is DOUBLE PRECISION
!>          The reciprocal of the condition number of the matrix A,
!>          computed as RCOND = 1/(norm(A) * norm(inv(A))).
!> 

WORK

!>          WORK is DOUBLE PRECISION array, dimension (3*N)
!> 

IWORK

!>          IWORK is INTEGER array, dimension (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 141 of file dtbcon.f.

Author

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Version 3.12.0 LAPACK