# [Numpy-discussion] Interpolation question

Andrea Gavana andrea.gavana@gmail....
Sun Mar 28 18:24:41 CDT 2010

```Hi Brennan & All,

On 28 March 2010 23:36, Brennan Williams wrote:
> Andrea Gavana wrote:
>> Let's see a couple of practical examples (I can share the data if
>> someone is interested).
>>
>>
> Definitely interested in helping solve this one so feel free to email
> the data (obviously not 1,000 Eclipse smspec and unsmry files although I
> can handle that without any problems).

It's 1 TB of data and my script took almost 4 hours in parallel on 4
processor over a network to reduce that huge amount of data to a tiny
406x7 matrix... but anyway, I'll see if I have the permission of
posting the data and I'll let you know. I could really use some
suggestions... or maybe a good kick in my a** telling me I am doing a
bunch of stupid things.

>> Example 1
>>
>> # o2 and o3 are the number of production wells, split into 2
>> # different categories
>> # inj is the number of injection wells
>> # fomts is the final oil recovery
>>
>> rbf = Rbf(oilPlateau, gasPlateau, gasInjPlateau, o2, o3, inj, fomts)
>>
>> op = [50380]
>> gp = [103014000]
>> gi = [53151000]
>> o2w = [45]
>> o3w = [20]
>> inw = [15]
>>
>>
> I take it all your inputs are float arrays? i.e. you just consider
> number of production wells as a floating point value.

They are floats, but it doesn't really matter as RBFs should treat
them all as floats. My results are the same whether I use "45" or
"45.0".

> I suppose strictly speaking o2 and o3 are not independent of eachother
> but I would guess that for the purposes of using Rbf it wouldn't be an
> issue.

They are independent: they are 2 completely different kind of wells,
o2 will give you much more gas while o3 much more oil.

It turns out that all interpolation methods *except* "linear" fail
miserably with huge errors even when I use exactly the same input
points as the original data points. If I use the "linear"
interpolator, I get errors in the range of

-1.16305401154e-005 1.29984131475e-006

In percentage, which is very good :-D. Unfortunately, when I input
even a single parameter value that is not in the original set, I still
get these non-physical results of oil production increasing when I
decrease the number of wells... Doh!

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 <==
```