DLANTP  -  return the value of the one norm, or the Frobe­
       nius norm, or the infinity norm, or the element of largest
       absolute  value  of  a  triangular  matrix  A, supplied in
       packed form


SYNOPSIS

       DOUBLE PRECISION FUNCTION DLANTP( NORM, UPLO, DIAG, N, AP,
                        WORK )

           CHARACTER    DIAG, NORM, UPLO

           INTEGER      N

           DOUBLE       PRECISION AP( * ), WORK( * )


PURPOSE

       DLANTP returns the value of the one norm, or the Frobenius
       norm, or the infinity norm,  or  the  element  of  largest
       absolute  value  of  a  triangular  matrix  A, supplied in
       packed form.


DESCRIPTION

       DLANTP returns the value

          DLANTP = ( 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  Frobe­
       nius 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 DLANTP as
               described above.

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

       DIAG    (input) CHARACTER*1
               Specifies whether or not the matrix A is unit tri­
               angular.  = 'N':  Non-unit triangular


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

       AP      (input) DOUBLE PRECISION array, dimension
               (N*(N+1)/2)
               The upper or lower  triangular  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.   Note that when DIAG = 'U', the elements
               of the array AP corresponding to the diagonal ele­
               ments  of the matrix A are not referenced, but are
               assumed to be one.

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


Man(1) output converted with man2html