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Name

ccdfft - 2D fourier transform of a map

Synopsis

ccdfft ini=image outr=image [parameter = value ...]

Description

ccdfft applies a Fast Fourier Transform to the input map(s).

Input maps musthave sizes which are powers of 2.

Parameters

The following parameters are recognized in any order if the keyword is also given:
inr=real-in-map
input file name, in image(5NEMO) format. This file is taken as the real part of the map to be transformed. [no default].
ini=ima-in-map
input file name, in image(5NEMO) format. This file is taken as the imaginary part of the map to be transformed. If no filename is given, the input map is assumed to be real. [default: not used].
outr=real-out-map
output file, will be in image(5NEMO) format. Will store the real part of the transform. [no default]
outi=ima-out-map
output file, will be in image(5NEMO) format. Will store the imaginary part of the transform [no default].

Timing

Performance on Rigel (SUN 3/160, 16Mhz): 
100 * 100    
200 * 200    
300 * 300    
512 * 512    

Storage Requirement

Totals to 24.NX.NY bytesm, which break down as follows: Only two images will be stored im memory, taking up 16.NX.NY bytes, for as long as images are stored in double. The actual fourier transform is done in float, and thiis requires a dynamically allocated scratch array of size 8.NX.NY.

See Also

ccdmath(1NEMO) , image(5NEMO) , tsf(1NEMO)

Author

Peter Teuben

Files


~/src/pjt/image      ccdfft.c ccdfft.1

Update History


 7-Jul-89    V1.0: Created    PJT

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