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



NAME
       DLANGE

SYNOPSIS
       DOUBLE PRECISION FUNCTION DLANGE (NORM, M, N, A, LDA, WORK)



PURPOSE
            DLANGE  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 matrix A.


       Returns:
           DLANGE

               DLANGE = ( 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 DLANGE as described
                     above.

           M         (input)
                     M is INTEGER
                     The number of rows of the matrix A.  M >= 0.  When M = 0,
                     DLANGE is set to zero.

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

           A         (input)
                     A is DOUBLE PRECISION array, dimension (LDA,N)
                     The m by n matrix A.

           LDA       (input)
                     LDA is INTEGER
                     The leading dimension of the array A.  LDA >= max(M,1).

           WORK      (output)
                     WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
                     where LWORK >= M when NORM = 'I'; otherwise, WORK is not
                     referenced.



LAPACK routine                  31 October 2017                      DLANGE(3)