more functions

["Arnaldo Leon" <arnaldo leon gmail com>]

Gnumeric is great, but I think I think it badly needs the following
(in order of importance):

1) a built-in linear/spline interpolation function.

2) 2-D interpolation (bi-linear and bi-cubic)

3) a transfer function/linear filter. This could work like
"=filter(numer,denom,data,time)" where "numer" and "denom" could point
to single cells or 1-D arrays and represent your transfer function,
"data" points to the data you want to filter, and "time" could be
either a time step or an array of time values. The output would be an
array of the same size as your input "data" (via CTRL-SHIFT-ENTER)

4) Fast-Fourier transforms!

5) eigenvalue and SVD matrix decompositions

Interpolation and filtering is something engineers do all the time. I
think this could be a huge win for bringing in more engineers to use
gnumeric. I used to work for an aerospace company and you won't
believe the amount of stuff that gets designed solely on Excel.

Also - I don't know if the number of data points on a plot is limited
(in Excel the max is 10,000), but it would be great if we could plot
millions of points on a chart, just like matlab can.

If you need a volunteer to code this stuff up, I might be able to find
some time :)

-aml