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 https://www.netlib.org/. See the section on FFTA for more discussion.