Provided by: liblapack-doc_3.3.1-1_all bug

NAME

       LAPACK-3 - estimates the reciprocal of the condition number of a triangular band matrix A,
       in either the 1-norm or the infinity-norm

SYNOPSIS

       SUBROUTINE ZTBCON( NORM, UPLO, DIAG, N, KD, AB, LDAB, RCOND, WORK, RWORK, INFO )

           CHARACTER      DIAG, NORM, UPLO

           INTEGER        INFO, KD, LDAB, N

           DOUBLE         PRECISION RCOND

           DOUBLE         PRECISION RWORK( * )

           COMPLEX*16     AB( LDAB, * ), WORK( * )

PURPOSE

       ZTBCON 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)) ).

ARGUMENTS

        NORM    (input) 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    (input) CHARACTER*1
                = 'U':  A is upper triangular;
                = 'L':  A is lower triangular.

        DIAG    (input) CHARACTER*1
                = 'N':  A is non-unit triangular;
                = 'U':  A is unit triangular.

        N       (input) INTEGER
                The order of the matrix A.  N >= 0.

        KD      (input) INTEGER
                The number of superdiagonals or subdiagonals of the
                triangular band matrix A.  KD >= 0.

        AB      (input) COMPLEX*16 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    (input) INTEGER
                The leading dimension of the array AB.  LDAB >= KD+1.

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

        WORK    (workspace) COMPLEX*16 array, dimension (2*N)

        RWORK   (workspace) DOUBLE PRECISION array, dimension (N)

        INFO    (output) INTEGER
                = 0:  successful exit
                < 0:  if INFO = -i, the i-th argument had an illegal value

 LAPACK routine (version 3.2)               April 2011                            ZTBCON(3lapack)