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

NAME
       SRC/slangt.f

SYNOPSIS
   Functions/Subroutines
       real function slangt (norm, n, dl, d, du)
           SLANGT returns the value of the 1-norm, Frobenius norm,
           infinity-norm, or the largest absolute value of any element of a
           general tridiagonal matrix.

Function/Subroutine Documentation
   real function slangt (character norm, integer n, real, dimension( * ) dl,
       real, dimension( * ) d, real, dimension( * ) du)
       SLANGT returns the value of the 1-norm, Frobenius norm, infinity-norm,
       or the largest absolute value of any element of a general tridiagonal
       matrix.

       Purpose:


            SLANGT  returns the value of the one norm,  or the Frobenius norm, or
            the  infinity norm,  or the  element of  largest absolute value  of a
            real tridiagonal matrix A.

       Returns
           SLANGT

               SLANGT = ( max(abs(A(i,j))), NORM = 'M' or 'm'
                        (
                        ( norm1(A),         NORM = '1', 'O' or 'o'
                        (
                        ( normI(A),         NORM = 'I' or 'i'
                        (
                        ( normF(A),         NORM = 'F', 'f', 'E' or 'e'

            where  norm1  denotes the  one norm of a matrix (maximum column sum),
            normI  denotes the  infinity norm  of a matrix  (maximum row sum) and
            normF  denotes the  Frobenius norm of a matrix (square root of sum of
            squares).  Note that  max(abs(A(i,j)))  is not a consistent matrix norm.

       Parameters
           NORM

                     NORM is CHARACTER*1
                     Specifies the value to be returned in SLANGT as described
                     above.

           N

                     N is INTEGER
                     The order of the matrix A.  N >= 0.  When N = 0, SLANGT is
                     set to zero.

           DL

                     DL is REAL array, dimension (N-1)
                     The (n-1) sub-diagonal elements of A.

           D

                     D is REAL array, dimension (N)
                     The diagonal elements of A.

           DU

                     DU is REAL array, dimension (N-1)
                     The (n-1) super-diagonal elements of A.

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 105 of file slangt.f.

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

LAPACK                          Version 3.12.0                 SRC/slangt.f(3)