dlange

Norm of a matrix

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

Lapack documentation
    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.

    Description
    ===========

    DLANGE returns the value

       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) CHARACTER*1
            Specifies the value to be returned in DLANGE as described
            above.

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

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

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

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

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

Syntax

anorm = dlange(A, norm)

Inputs (2)

A

Type: Real[:,:]

Description: Real matrix A

norm

Default Value: "1"

Type: String

Description: Specifies the norm, i.e., 1, I, F, M

Outputs (1)

anorm

Type: Real

Description: Norm of A