# CentOS 7.0 - man page for slansp (centos section 3)

```slansp.f(3)							      LAPACK							       slansp.f(3)

NAME
slansp.f -

SYNOPSIS
Functions/Subroutines
REAL function slansp (NORM, UPLO, N, AP, WORK)
SLANSP returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a
symmetric matrix supplied in packed form.

Function/Subroutine Documentation
REAL function slansp (characterNORM, characterUPLO, integerN, real, dimension( * )AP, real, dimension( * )WORK)
SLANSP returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a
symmetric matrix supplied in packed form.

Purpose:

SLANSP  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.

Returns:
SLANSP

SLANSP = ( 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.

Parameters:
NORM

NORM is CHARACTER*1
Specifies the value to be returned in SLANSP as described
above.

UPLO

UPLO is 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

N is INTEGER
The order of the matrix A.  N >= 0.  When N = 0, SLANSP is
set to zero.

AP

AP is REAL 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

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

Author:
Univ. of Tennessee

Univ. of California Berkeley