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# NAG Toolbox: nag_sum_conjugate_hermitian_rfmt (c06gb)

## Purpose

nag_sum_conjugate_hermitian_rfmt (c06gb) forms the complex conjugate of a Hermitian sequence of n$n$ data values.
Note: this function is scheduled to be withdrawn, please see c06gb in Advice on Replacement Calls for Withdrawn/Superseded Routines..

## Syntax

[x, ifail] = c06gb(x, 'n', n)
[x, ifail] = nag_sum_conjugate_hermitian_rfmt(x, 'n', n)

## Description

This is a utility function for use in conjunction with nag_sum_fft_real_1d_nowork (c06ea), nag_sum_fft_hermitian_1d_nowork (c06eb), nag_sum_fft_real_1d_rfmt (c06fa) or nag_sum_fft_hermitian_1d_rfmt (c06fb) to calculate inverse discrete Fourier transforms (see the C06 Chapter Introduction).

None.

## Parameters

### Compulsory Input Parameters

1:     x(n) – double array
n, the dimension of the array, must satisfy the constraint n1${\mathbf{n}}\ge 1$.
If the data values zj${z}_{j}$ are written as xj + i yj${x}_{j}+i{y}_{j}$ and if x is declared with bounds (0 : n1)$\left(0:{\mathbf{n}}-1\right)$ in the function from which nag_sum_conjugate_hermitian_rfmt (c06gb) is called, then for 0 j n / 2$0\le j\le n/2$, x(j)${\mathbf{x}}\left(j\right)$ must contain xj${x}_{j}$ ( = xnj$\text{}={x}_{n-j}$), while for n / 2 < j n1$n/2, x(j)${\mathbf{x}}\left(j\right)$ must contain yj${-y}_{j}$ ( = ynj$\text{}={y}_{n-j}$). In other words, x must contain the Hermitian sequence in Hermitian form. (See also Section [Real transforms] in the C06 Chapter Introduction.)

### Optional Input Parameters

1:     n – int64int32nag_int scalar
Default: The dimension of the array x.
n$n$, the number of data values.
Constraint: n1${\mathbf{n}}\ge 1$.

None.

### Output Parameters

1:     x(n) – double array
The imaginary parts yj${y}_{j}$ are negated. The real parts xj${x}_{j}$ are not referenced.
2:     ifail – int64int32nag_int scalar
${\mathrm{ifail}}={\mathbf{0}}$ unless the function detects an error (see [Error Indicators and Warnings]).

## Error Indicators and Warnings

Errors or warnings detected by the function:
ifail = 1${\mathbf{ifail}}=1$
 On entry, n < 1${\mathbf{n}}<1$.

## Accuracy

Exact.

The time taken by nag_sum_conjugate_hermitian_rfmt (c06gb) is negligible.

## Example

```function nag_sum_conjugate_hermitian_rfmt_example
x = [2.483612111433092;
-0.2659851230605639;
-0.2576817880971343;
-0.2563629394821892;
0.05806233079461325;
0.2029789655613654;
0.5308983652332478];
[xOut, ifail] = nag_sum_conjugate_hermitian_rfmt(x)
```
```

xOut =

2.4836
-0.2660
-0.2577
-0.2564
-0.0581
-0.2030
-0.5309

ifail =

0

```
```function c06gb_example
x = [2.483612111433092;
-0.2659851230605639;
-0.2576817880971343;
-0.2563629394821892;
0.05806233079461325;
0.2029789655613654;
0.5308983652332478];
[xOut, ifail] = c06gb(x)
```
```

xOut =

2.4836
-0.2660
-0.2577
-0.2564
-0.0581
-0.2030
-0.5309

ifail =

0

```

PDF version (NAG web site, 64-bit version, 64-bit version)
Chapter Contents
Chapter Introduction
NAG Toolbox

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