# [Numpy-discussion] Interpolation question

Andrea Gavana andrea.gavana at gmail.com
Mon Mar 29 17:45:30 EDT 2010

```Hi Chris and All,

On 29 March 2010 22:35, Christopher Barker wrote:
> Andrea Gavana wrote:
>>>> Scaling each axis by its standard deviation is a typical first start.
>>>> Shifting and scaling the values such that they each go from 0 to 1 is
>>>> another useful thing to try.
>>> Ah, magnifico! Thank you Robert and Friedrich, it seems to be working
>>> now...
>
> One other thought -- core to much engineering is dimensional analysis --
> you know how we like those non-dimensional number!
>
> I think this situation is less critical, as you are interpolating, not
> optimizing or something, but many interpolation methods are built on the
> idea of some data points being closer than others to your point of interest.
>
> Who is to say if a point that is 2 hours away is closer or father than
> one 2 meters away? This is essentially what you are doing.
>
> Scaling everything to the same range is a start, but then you've still
> given them an implicit weighting.
>
> An alternative to to figure out a way to non-dimensionalize your
> parameters -- that *may* give you a more physically based scaling.
>
> And you might invent the "Gavana Number" in the process ;-)

Might be :-D . At the moment I am pretty content with what I have got,
it seems to be working fairly well although I didn't examine all the
possible cases and it is very likely that my little tool will break
disastrously for some combinations of parameters. However, I am not
sure I am allowed to post an image comparing the "real" simulation
with the prediction of the interpolated proxy model, but if you could
see it, you would surely agree that it is a very reasonable approach.
It seems to good to be true :-D .

Again, this is mainly due to the fact that we have a very extensive
set of simulations which cover a wide range of combinations of
parameters, so the interpolation itself is only doing its job
correctly. I don't think the technique can be applied blindly to
whatever oil/gas/condensate /whatever reservoir, as non-linearities in
fluid flow simulations appear where you least expect them, but it
seems to be working ok (up to now) for our field (which is, by the
way, one of the most complex and less understood condensate reservoir
out there).

Andrea.

"Imagination Is The Only Weapon In The War Against Reality."
http://xoomer.alice.it/infinity77/

==> Never *EVER* use RemovalGroup for your house removal. You'll
regret it forever.
http://thedoomedcity.blogspot.com/2010/03/removal-group-nightmare.html <==

```

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