private static void TestFastDctFftInvertibility()
{
for (int i = 0, prev = 0; i <= 30; i++)
{
int len = (int)Math.Round(Math.Pow(1000000, i / 30.0));
if (len <= prev)
{
continue;
}
prev = len;
double[] vector = RandomVector(len);
double[] temp = (double[])vector.Clone();
FastDctFft.Transform(temp);
FastDctFft.InverseTransform(temp);
for (int j = 0; j < temp.Length; j++)
{
temp[j] /= len / 2.0;
}
AssertArrayEquals(vector, temp, EPSILON);
}
}
private static void TestFastDctFftVsNaive()
{
for (int i = 0, prev = 0; i <= 100; i++)
{
int len = (int)Math.Round(Math.Pow(3000, i / 100.0));
if (len <= prev)
{
continue;
}
prev = len;
double[] vector = RandomVector(len);
double[] expect = NaiveDct.Transform(vector);
double[] actual = (double[])vector.Clone();
FastDctFft.Transform(actual);
AssertArrayEquals(expect, actual, EPSILON);
expect = NaiveDct.InverseTransform(vector);
actual = (double[])vector.Clone();
FastDctFft.InverseTransform(actual);
AssertArrayEquals(expect, actual, EPSILON);
}
}