**fScan Reference Manual, Chapter 2 (CmdLineOptions:Expr): fft**
===== fft -- Perform a fast Fourier transform =====
 **usage:  -expr fft flag [outwdsiz]**

The FFT expression performs a fast Fourier transform (FFT) on an entire data set.
The FLAG argument controls options as:

FLAG:\\
  * 1 - frequency space to image space (default: image to frequency)1-dimensional FFT
  * 2 - 2-dimensional FFT (default: 1-dimensional FFT)
  * 4 - input has phase (default: magnitude only, set phase to 0)
  * 8 - output is complex (default: single value, magnitude only)
  * 16 - output is phase only
  * 32 - output is real only
  * 48 - output is imaginary only
  * 64 - magnitude and phase are highest dimension (default: lowest dimension)

OUTWDSIZ is the output word size. The default is float32 if FLAG indicates single values ((FLAG&56)!=8), or cpx_float32 if (FLAG&56)==8.

**See Also:**\\
[[jvs:fscan|fScan Home]], 
[[jvs:fscan:manual|fScan Manual]], 
[[jvs:fscan:manual:chapter2|CmdLineOptions]], 
[[jvs:fscan:manual:chapter2:expression|Expression Command]], 
[[jvs:fscan:manual:help|Manual Help]]