CLANTP  -  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

       REAL FUNCTION CLANTP( NORM, UPLO, DIAG, N, AP, WORK )

           CHARACTER DIAG, NORM, UPLO

           INTEGER   N

           REAL      WORK( * )

           COMPLEX   AP( * )


PURPOSE

       CLANTP 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

       CLANTP returns the value

          CLANTP = ( 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  CLANTP  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

               = 'U':  Unit triangular

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

       AP      (input) COMPLEX 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) REAL array, dimension (LWORK),
               where LWORK >= N when NORM = 'I'; otherwise,  WORK
               is not referenced.


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