1: $y (n)$ – double array: If y is declared with bounds $(0 : n - 1)$ in the function from which nag_sum_conjugate_complex_sep (c06gc) is called, then $y (j)$ must contain the imaginary part of the $j$ th data value, for $0 \leq j \leq n - 1$ .

Optional Input Parameters

1: $n$ – int64int32nag_int scalar: Default: the dimension of the array y.
$n$ , the number of data values.

Constraint: $n \geq 1$ .

Output Parameters

1: $y (n)$ – double array: These values are negated.
2: $ifail$ – int64int32nag_int scalar: $ifail = 0$ unless the function detects an error (see Error Indicators and Warnings).

Error Indicators and Warnings

Errors or warnings detected by the function:

$ifail = 1$

On entry,

n < 1

$ifail = - 99$: An unexpected error has been triggered by this routine. Please contact NAG.

$ifail = - 399$: Your licence key may have expired or may not have been installed correctly.

$ifail = - 999$: Dynamic memory allocation failed.

Accuracy

Exact.

Further Comments

The time taken by nag_sum_conjugate_complex_sep (c06gc) is negligible.

Example

This example reads in a sequence of complex data values and prints their inverse discrete Fourier transform as computed by calling nag_sum_conjugate_complex_sep (c06gc), followed by nag_sum_fft_complex_1d_nowork (c06ec) and nag_sum_conjugate_complex_sep (c06gc) again.

Open in the MATLAB editor: c06gc_example

function c06gc_example


fprintf('c06gc example results\n\n');

x_r = [ 0.34907;  0.54890;  0.74776;  0.94459;  1.13850; 1.32850;  1.51370];
x_i = [-0.37168; -0.35669; -0.31175; -0.23702; -0.13274; 0.00074;  0.16298];

z = x_r + i*x_i;
disp('Complex data:');
disp(z);

[x_r, x_i, ifail] = c06ec(x_r, x_i);

z = x_r + i*x_i;
disp('Complex Fourier coeffients:');
disp(z);

[x_i, ifail] = c06gc(x_i);
[x_r, x_i, ifail] = c06ec(x_r, x_i);
[x_i, ifail] = c06gc(x_i);

z = x_r + i*x_i;
disp('Retrieved complex data:');
disp(z);

c06gc example results

Complex data:
   0.3491 - 0.3717i
   0.5489 - 0.3567i
   0.7478 - 0.3118i
   0.9446 - 0.2370i
   1.1385 - 0.1327i
   1.3285 + 0.0007i
   1.5137 + 0.1630i

Complex Fourier coeffients:
   2.4836 - 0.4710i
  -0.5518 + 0.4968i
  -0.3671 + 0.0976i
  -0.2877 - 0.0586i
  -0.2251 - 0.1748i
  -0.1483 - 0.3084i
   0.0198 - 0.5650i

Retrieved complex data:
   0.3491 - 0.3717i
   0.5489 - 0.3567i
   0.7478 - 0.3117i
   0.9446 - 0.2370i
   1.1385 - 0.1327i
   1.3285 + 0.0007i
   1.5137 + 0.1630i

PDF version (NAG web site, 64-bit version, 64-bit version)

Chapter Contents

Chapter Introduction

NAG Toolbox