\brief \b ESMF_DLANSY returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real symmetric matrix. \htmlonly Download ESMF_DLANSY + dependencies [TGZ] [ZIP] [TXT] \endhtmlonly \par Purpose:
\verbatim
ESMF_DLANSY 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 matrix A. \endverbatim
\return ESMF_DLANSY \verbatim
ESMF_DLANSY = ( 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_DLANSY as described above. \endverbatim
\param[in] UPLO \verbatim UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix A is to be referenced. = ‘U’: Upper triangular part of A is referenced = ‘L’: Lower triangular part of A is referenced \endverbatim
\param[in] N \verbatim N is INTEGER The order of the matrix A. N >= 0. When N = 0, ESMF_DLANSY is set to zero. \endverbatim
\param[in] A \verbatim A is DOUBLE PRECISION array, dimension (LDA,N) The symmetric matrix A. If UPLO = ‘U’, the leading n by n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = ‘L’, the leading n by n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. \endverbatim
\param[in] LDA \verbatim LDA is INTEGER The leading dimension of the array A. LDA >= max(N,1). \endverbatim
\param[out] WORK \verbatim WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)), where LWORK >= N when NORM = ‘I’ or ‘1’ or ‘O’; otherwise, WORK is not referenced. \endverbatim \author Univ. of Tennessee \author Univ. of California Berkeley \author Univ. of Colorado Denver \author NAG Ltd. \date December 2016 \ingroup doubleSYauxiliary
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| character(len=1) | :: | NORM | ||||
| character(len=1) | :: | UPLO | ||||
| integer | :: | N | ||||
| double precision | :: | A(LDA,*) | ||||
| integer | :: | LDA | ||||
| double precision | :: | WORK(*) |