redhat man page for slangt

SLANGT(l)								 )								 SLANGT(l)

NAME
       SLANGT  - return 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

SYNOPSIS
       REAL FUNCTION SLANGT( NORM, N, DL, D, DU )

	   CHARACTER NORM

	   INTEGER   N

	   REAL      D( * ), DL( * ), DU( * )

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.

DESCRIPTION
       SLANGT returns the value

	  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  matrix norm.

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

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

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

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

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

LAPACK version 3.0						   15 June 2000 							 SLANGT(l)