NAG FL Interface
f06rpf (dlanst)

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FL Name Style:

FL Specification Language:

1 Purpose

f06rpf returns, via the function name, the value of the 1-norm, the -norm, the Frobenius norm, or the maximum absolute value of the elements of a real n×n symmetric tridiagonal matrix A.

2 Specification

Fortran Interface
Function f06rpf ( norm, n, d, e)
Real (Kind=nag_wp) :: f06rpf
Integer, Intent (In) :: n
Real (Kind=nag_wp), Intent (In) :: d(*), e(*)
Character (1), Intent (In) :: norm
C Header Interface
#include <nag.h>
double  f06rpf_ (const char *norm, const Integer *n, const double d[], const double e[], const Charlen length_norm)
The routine may be called by the names f06rpf or nagf_blas_dlanst.

3 Description


4 References


5 Arguments

1: norm Character(1) Input
On entry: specifies the value to be returned.
norm='1' or 'O'
The 1-norm.
The -norm.
norm='F' or 'E'
The Frobenius (or Euclidean) norm.
The value maxi,j|aij| (not a norm).
Constraint: norm='1', 'O', 'I', 'F', 'E' or 'M'.
2: n Integer Input
On entry: n, the order of the matrix A.
When n=0, f06rpf returns zero.
Constraint: n0.
3: d(*) Real (Kind=nag_wp) array Input
Note: the dimension of the array d must be at least max(1,n) .
On entry: the n diagonal elements of the tridiagonal matrix A.
4: e(*) Real (Kind=nag_wp) array Input
Note: the dimension of the array e must be at least max(1,n-1) .
On entry: the (n-1) subdiagonal or superdiagonal elements of the tridiagonal matrix A.

6 Error Indicators and Warnings


7 Accuracy

Not applicable.

8 Parallelism and Performance

f06rpf is not threaded in any implementation.

9 Further Comments


10 Example