ESMF_DLANGE Function

function ESMF_DLANGE(NORM, M, N, A, LDA, WORK)

\brief \b ESMF_DLANGE \htmlonly Download ESMF_DLANGE + dependencies [TGZ] [ZIP] [TXT] \endhtmlonly \par Purpose:

\verbatim

ESMF_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. \endverbatim

\return ESMF_DLANGE \verbatim

ESMF_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. \endverbatim \param[in] NORM \verbatim NORM is CHARACTER*1 Specifies the value to be returned in ESMF_DLANGE as described above. \endverbatim

\param[in] M \verbatim M is INTEGER The number of rows of the matrix A. M >= 0. When M = 0, ESMF_DLANGE is set to zero. \endverbatim

\param[in] N \verbatim N is INTEGER The number of columns of the matrix A. N >= 0. When N = 0, ESMF_DLANGE is set to zero. \endverbatim

\param[in] A \verbatim A is DOUBLE PRECISION array, dimension (LDA,N) The m by n matrix A. \endverbatim

\param[in] LDA \verbatim LDA is INTEGER The leading dimension of the array A. LDA >= max(M,1). \endverbatim

\param[out] WORK \verbatim WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)), where LWORK >= M when NORM = ‘I’; otherwise, WORK is not referenced. \endverbatim \author Univ. of Tennessee \author Univ. of California Berkeley \author Univ. of Colorado Denver \author NAG Ltd. \date November 2011 \ingroup doubleGEauxiliary

Arguments

Type IntentOptional Attributes Name
character(len=1) :: NORM
integer :: M
integer :: N
double precision :: A(LDA,*)
integer :: LDA
double precision :: WORK(*)

Return Value doubleprecision