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XMM-Newton Science Analysis System


ssclib (ssclib-3.29.3) [xmmsas_20070708_1801-7.1.0]

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Some utilities and definitions for applications which make use of the FFTW library

Module name: fftw_aux

Author: Ian Stewart (University of Leicester, ims@star.le.ac.uk)

This module is meant to be used in conjunction with the Fast Fourier Transform package fftw which comes with the sas. The module contains a header in which some useful variables are declared, as well as the following routine:

  function findNextHighest2357multiple(i) result(result)
    integer, intent(in) :: i
  end function findNextHighest2357multiple

This function is designed to look for the smallest integer that satisfies the following conditions: (i) it is greater than or equal to the argument i; (ii) it is a product only of the numbers 2, 3, 5 and 7. The fftw transform works most efficiently on arrays which have dimensions which are products of small primes.