Abstract Class representing FFT's of complex, single precision data. Concrete classes are typically named ComplexFloatFFT_method, implement the FFT using some particular method.
Complex data is represented by 2 double values in sequence: the real and imaginary parts. Thus, in the default case (i0=0, stride=2), N data points is represented by a double array dimensioned to 2*N. To support 2D (and higher) transforms, an offset, i0 (where the first element starts) and stride (the distance from the real part of one value, to the next: at least 2 for complex values) can be supplied. The physical layout in the array data, of the mathematical data d[i] is as follows:
Re(d[i]) = data[i0 + stride*i]
Im(d[i]) = data[i0 + stride*i+1]
The transformed data is returned in the original data array in
wrap-around order.