nag_conjugate_hermitian (c06gbc) (PDF version)
c06 Chapter Contents
c06 Chapter Introduction
NAG C Library Manual

NAG Library Function Document

nag_conjugate_hermitian (c06gbc)

+ Contents

    1  Purpose
    7  Accuracy

1  Purpose

nag_conjugate_hermitian (c06gbc) forms the complex conjugate of a Hermitian sequence of n  data values.

2  Specification

#include <nag.h>
#include <nagc06.h>
void  nag_conjugate_hermitian (Integer n, double x[], NagError *fail)

3  Description

This is a utility function for use in conjunction with nag_fft_real (c06eac) and nag_fft_hermitian (c06ebc), to calculate inverse discrete Fourier transforms.

4  References

None.

5  Arguments

1:     nIntegerInput
On entry: the number of data values, n .
Constraint: n1 .
2:     x[n]doubleInput/Output
On entry: if the data values z j  are written as x j + i y j , then for 0 j n / 2 , x[j]  must contain x j = x n-j , while for n / 2 < j n - 1 , x[j]  must contain - y j = y n-j . In other words, x must contain the Hermitian sequence in Hermitian form.
On exit: the imaginary parts y j  are negated. The real parts x j  are not referenced.
3:     failNagError *Input/Output
The NAG error argument (see Section 3.6 in the Essential Introduction).

6  Error Indicators and Warnings

NE_INT_ARG_LT
On entry, n=value.
Constraint: n1.

7  Accuracy

Exact.

8  Further Comments

The time taken is negligible.

9  Example

This program reads in a sequence of real data values, calls nag_fft_real (c06eac) followed by nag_conjugate_hermitian (c06gbc) to compute their inverse discrete Fourier transform, and prints this after expanding it from Hermitian form into a full complex sequence.

9.1  Program Text

Program Text (c06gbce.c)

9.2  Program Data

Program Data (c06gbce.d)

9.3  Program Results

Program Results (c06gbce.r)


nag_conjugate_hermitian (c06gbc) (PDF version)
c06 Chapter Contents
c06 Chapter Introduction
NAG C Library Manual

© The Numerical Algorithms Group Ltd, Oxford, UK. 2012