Re: FFT and continuous data

On May 23, 3:31 pm, Gordon Sande <g.sa...@xxxxxxxxxxxxxxxx> wrote:
On 2007-05-23 11:15:33 -0300, colin.tor...@xxxxxxxxx said:

Hi,
I am working with a velocity field in fourier space and I need to find
the time domain velocity at a given point. As far as I can make out
the FFT is based on returning values at the grid points only, is this
correct? Is there any other algorithm that will map a discrete field
in fourier space onto a single point which isn't on the grid? I know I
can just do a normal transform on an intermediate point or an FFT and
interpolate but are these my only options?
Thanks

For ONE point it is hard to beat just summing the obvious series.
If the velocities are structured then you might want to use that
structure.

So for a single point the naive algorithm is the best solution? If I
have muliple points and use an interpolation of the transformed data
is there an optimum interpolation method?
Thanks

.

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