Appendix A Sec24.
FFT_INVERSE
FFT_INVERSE(AR, AI) computes the inverse Fast Fourier Transform of the two frequency series AR and AI
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Arguments: |
AR |
Real part of an FFT transform. Variable with a frequency axis; may be a function of x, y, and/or z |
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AI |
Imaginary part of an FFT transform. Variable with a frequency axis; may be a function of x, y, and/or z |
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Result Axes: |
X |
Inherited from AR, AI |
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Y |
Inherited from AR, AI |
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Z |
Inherited from AR, AI |
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T |
Abstract axis: 2*length of input frequency axes of AR and AI |
The returned time axis is abstract; the user will need to regrid it to the appropriate time axis.
See the note in chapter 3 above, on the context of variables passed to functions.
The code is based on the FFT routines in Swarztrauber's FFTPACK available at www.netlib.org. See the section on FFTA for more discussion. For further discussion of the FFTPACK code, please see the document, Notes on FFTPACK - A Package of Fast Fourier Transform Programs.