public static void Draw( Rect position, ComplexNumber[] data )
{
float[] realData = new float[ data.Length ];
for (int i=0; i<realData.Length; i++)
{
realData[ i ] = data[ i ].Magnitude;
}
Draw( position, realData );
}
/// <summary>
/// Fasts the fourier transform.
/// </summary>
/// <returns>
/// The fourier transform.
/// </returns>
/// <param name='realData'>
/// Real data.
/// </param>
public static ComplexNumber[] FastFourierTransform( float[] realData )
{
ComplexNumber[] x = new ComplexNumber[ realData.Length ];
for (int i=0; i<x.Length; i++)
{
x[i] = new ComplexNumber( realData[ i ] );
}
return FastFourierTransform( x );
}
/// <summary>
/// Fasts the fourier transform.
/// </summary>
/// <returns>
/// The fourier transform.
/// </returns>
/// <param name='x'>
/// X.
/// </param>
public static ComplexNumber[] FastFourierTransform( ComplexNumber[] x )
{
int N = x.Length; // The total number of samples
if (N == 1)
{
// If we have only one sample, it is our result
return x;
}
// Split data set in half:
ComplexNumber[] E = new ComplexNumber[ N/2 ];
ComplexNumber[] D = new ComplexNumber[ N/2 ];
for (int i=0; i<N/2; i++)
{
E[ i ] = x[ 2 * i ];
D[ i ] = x[ 2 * i + 1 ];
}
// Recurse.
E = FastFourierTransform( E );
D = FastFourierTransform( D );
// Multiply D by complex number (for reasons)
for (int k=0; k<N/2; k++)
{
ComplexNumber temp = ComplexNumber.FromPolar( 1, -2 * Mathf.PI * k / N );
D[k] *= temp;
}
// Define the result array:
ComplexNumber[] X = new ComplexNumber[ N ];
// Add Complex Numbers
for (int k=0; k<N/2; k++)
{
X[ k ] = E[ k ] + D[ k ];
X[ k + N/2 ] = E[ k ] - D[ k ];
}
// Return result
return X;
}
