The following functions
convert data from the packed formats to a usual complex data format using the FFT symmetry property for transforming real data. The output data is complex, the output array length is defined by the number of complex elements in the output vector. Note that the output array size is two times as big as the input array size. The data stored in
format require a bigger array than the other formats. Even and odd length arrays have some specific features discussed for each function separately.