DLANTP(3)      LAPACK routine of NEC Numeric Library Collection      DLANTP(3)



NAME
       DLANTP

SYNOPSIS
       DOUBLE PRECISION FUNCTION DLANTP (NORM, UPLO, DIAG, N, 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.


       Returns:
           DLANTP

               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  Frobenius norm of a matrix (square root of sum of
            squares).  Note that  max(abs(A(i,j)))  is not a consistent matrix norm.




ARGUMENTS
           NORM      (input)
                     NORM is CHARACTER*1
                     Specifies the value to be returned in DLANTP as described
                     above.

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

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

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

           AP        (input)
                     AP is 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 elements of the matrix A are
                     not referenced, but are assumed to be one.

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



LAPACK routine                  31 October 2017                      DLANTP(3)