5.1 Introduction to FFTs

There are two main types of Discrete Fourier Transform (DFT):

• routines for the transformation of complex data: in the ACML, these routines have names beginning with ZFFT or CFFT, for double and single precision, respectively;
• routines for the transformation of real to complex data and vice versa: in the ACML the names for the former begin with DZFFT or SCFFT, for double and single precision, respectively; the names for the latter begin with ZDFFT or CSFFT.

The following subsections provide definitions of the DFT for complex and real data types, and some guidelines on the efficient use of the ACML FFT routines.

• DFT Complex: Transform definitions and storage for complex data
• DFT Real: Transform definitions and storage for real data
• Efficiency: Efficiency
• Plans: Default and generated FFT plans