dlansp(3F)

NAME
     DLANSP - 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
     symmetric matrix A, supplied in packed form

SYNOPSIS
     DOUBLE PRECISION FUNCTION DLANSP( NORM, UPLO, N, AP, WORK )

         CHARACTER    NORM, UPLO

         INTEGER      N

         DOUBLE       PRECISION AP( * ), WORK( * )

PURPOSE
     DLANSP  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,  supplied in packed form.


DESCRIPTION
     DLANSP returns the value

        DLANSP = ( 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 DLANSP as described above.

     UPLO    (input) CHARACTER*1
             Specifies whether the upper or lower triangular part of the
             symmetric matrix A is supplied.  = 'U':  Upper triangular part of
             A is supplied
             = 'L':  Lower triangular part of A is supplied

     N       (input) INTEGER
             The order of the matrix A.  N >= 0.  When N = 0, DLANSP is set to
             zero.
     AP      (input) DOUBLE PRECISION array, dimension (N*(N+1)/2)
             The upper or lower triangle of the symmetric matrix A, packed
             columnwise in a linear array.  The j-th column of A is stored in
             the array AP as follows:  if UPLO = 'U', AP(i + (j-1)*j/2) =
             A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) =
             A(i,j) for j<=i<=n.

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