SRC/zgtcon.f(3)            Library Functions Manual            SRC/zgtcon.f(3)

NAME
       SRC/zgtcon.f

SYNOPSIS
   Functions/Subroutines
       subroutine zgtcon (norm, n, dl, d, du, du2, ipiv, anorm, rcond, work,
           info)
           ZGTCON

Function/Subroutine Documentation
   subroutine zgtcon (character norm, integer n, complex*16, dimension( * )
       dl, complex*16, dimension( * ) d, complex*16, dimension( * ) du,
       complex*16, dimension( * ) du2, integer, dimension( * ) ipiv, double
       precision anorm, double precision rcond, complex*16, dimension( * )
       work, integer info)
       ZGTCON

       Purpose:


           !>
           !> ZGTCON estimates the reciprocal of the condition number of a complex
           !> tridiagonal matrix A using the LU factorization as computed by
           !> ZGTTRF.
           !>
           !> 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*16 array, dimension (N-1)
           !>          The (n-1) multipliers that define the matrix L from the
           !>          LU factorization of A as computed by ZGTTRF.
           !>

           D

           !>          D is COMPLEX*16 array, dimension (N)
           !>          The n diagonal elements of the upper triangular matrix U from
           !>          the LU factorization of A.
           !>

           DU

           !>          DU is COMPLEX*16 array, dimension (N-1)
           !>          The (n-1) elements of the first superdiagonal of U.
           !>

           DU2

           !>          DU2 is COMPLEX*16 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 DOUBLE PRECISION
           !>          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 DOUBLE PRECISION
           !>          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*16 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 zgtcon.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/zgtcon.f(3)