private static void r4vec_sft_test()
//****************************************************************************80
//
// Purpose:
//
// R4VEC_SFT_TEST tests R4VEC_SFTB and R4VEC_SFTF.
//
// Licensing:
//
// This code is distributed under the GNU LGPL license.
//
// Modified:
//
// 10 June 2010
//
// Author:
//
// John Burkardt
//
{
const float ahi = 5.0f;
const float alo = 0.0f;
float azero = 0;
int i;
const int n = 36;
Console.WriteLine("");
Console.WriteLine("R4VEC_SFT_TEST");
Console.WriteLine(" R4VEC_SFTF computes the forward slow Fourier transform.");
Console.WriteLine(" R4VEC_SFTB computes the backward slow Fourier transform.");
Console.WriteLine("");
Console.WriteLine(" The number of data values, N = " + n + "");
int seed = 123456789;
float[] x = UniformRNG.r4vec_uniform_ab_new(n, alo, ahi, ref seed);
typeMethods.r4vec_print_part(n, x, 10, " The original data:");
//
// Compute the slow Fourier transform of the data.
//
float[] a = new float[n / 2];
float[] b = new float[n / 2];
Slow.r4vec_sftf(n, x, ref azero, ref a, ref b);
Console.WriteLine("");
Console.WriteLine(" A (cosine) coefficients:");
Console.WriteLine("");
Console.WriteLine(" " + 0.ToString(CultureInfo.InvariantCulture).PadLeft(4)
+ " " + azero.ToString(CultureInfo.InvariantCulture).PadLeft(14) + "");
for (i = 0; i < n / 2; i++)
{
Console.WriteLine(" " + i.ToString(CultureInfo.InvariantCulture).PadLeft(4)
+ " " + a[i].ToString(CultureInfo.InvariantCulture).PadLeft(14) + "");
}
Console.WriteLine("");
Console.WriteLine(" B (sine) coefficients:");
Console.WriteLine("");
for (i = 0; i < n / 2; i++)
{
Console.WriteLine(" " + i.ToString(CultureInfo.InvariantCulture).PadLeft(4)
+ " " + b[i].ToString(CultureInfo.InvariantCulture).PadLeft(14) + "");
}
//
// Now try to retrieve the data from the coefficients.
//
float[] z = Slow.r4vec_sftb(n, azero, a, b);
typeMethods.r4vec_print_part(n, z, 10, " The retrieved data:");
}
