SLANST(3)      LAPACK routine of NEC Numeric Library Collection      SLANST(3)



NAME
       SLANST

SYNOPSIS
       REAL FUNCTION SLANST (NORM, N, D, E)



PURPOSE
            SLANST  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 symmetric tridiagonal matrix A.


       Returns:
           SLANST

               SLANST = ( 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.




ARGUMENTS
           NORM      (input)
                     NORM is CHARACTER*1
                     Specifies the value to be returned in SLANST as described
                     above.

           N         (input)
                     N is INTEGER
                     The order of the matrix A.  N >= 0.  When N = 0, SLANST is
                     set to zero.

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

           E         (input)
                     E is REAL array, dimension (N-1)
                     The (n-1) sub-diagonal or super-diagonal elements of A.



LAPACK routine                  31 October 2017                      SLANST(3)