Purpose

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  This procedure calculates the vector wavenumber at each pixel in
  an n-dim fft array. It's like indices.pro, except that the k's are
  normalized and shifted correctly to match the default
  structure of IDL's FFT command.

Inputs

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  array: An n-dimensional array (presumably an fft of something)

Keyword Parameters

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  t: The spacing between each pixel in the pre-FT space. Scalar or
    vector of length equal to the dimensionality of array. The
    k value at each pixel in FFT space is 2 pi n/(N * T), where n is
    an integer, N is the number of pixels along a dimension, and T
    is the spacing (see FFT documentation). Defaults to 1

Outputs

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  k1: An array with the same shape as the input, giving the k1
      coordinate at each pixel
  k2-k8: Ditto, for the other dimensions

Modification History

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  2010-07-29: Created by Chris Beaumont