Re: A new proof of the superiority of set oriented approaches: numerical/time serie linear interpolation

On 29 avr, 20:24, Tonkuma <tonk..._at_jp.ibm.com> wrote:
> On Apr 29, 7:04 pm, Cimode <cim..._at_hotmail.com> wrote:
>
>
>
> > ID Distance ArrivalTime
> > 24 0.289 2000-01-01 06:29:00.000
> > 25 0.193 NULL --> 1st value to be interpolated
> > 26 0.299 NULL --> 2nd value to be interpolated
> > 27 0.131 NULL --> 3rd value to be interpolated
> > 28 0.444 NULL --> 4th value to be interpolated
> > 29 0.16 NULL --> 5th value to be interpolated
> > 30 0.665 NULL --> 6th value to be interpolated
> > 31 0.186 2000-01-01 06:33:00.000
>
> > As a result, I obtained the following interpolation...
>
> > ID Distance ArrivalTime
> > 24 0.289 2000-01-01 06:29:00.000
> > 25 0.193 2000-01-01 06:29:24.000
> > 26 0.299 2000-01-01 06:29:37.000
> > 27 0.131 2000-01-01 06:29:16.000
> > 28 0.444 2000-01-01 06:29:56.000
> > 29 0.160 2000-01-01 06:29:20.000
> > 30 0.665 2000-01-01 06:30:24.000
> > 31 0.186 2000-01-01 06:33:00.000
>
> I couldn't understand well the meaning of ID(pehaps station ID) and
> Distance.
> Looking your result rows with NULL ArrivalTime, ID is sequenced by
> Distance.
> But, rows with NOT NULL ArrivalTime seems that station is sequenced by
> ID.
> That means lowest ID 24 is start station and largest ID 31 is
> destination station.
> But, distance of 24 is not 0, it is 0.289. So, my question is Distant
> of ID 24 is from where?
>From ID 23
> And Distance of ID 31(0.186) is from where?
>From interpolated value of ID = 30 according to the formula.

> I think my question would be more clear, if result rows sequenced by
> distance.
> Like this:
> ID Distance ArrivalTime
> 27 0.131 2000-01-01 06:29:16.000
> 29 0.160 2000-01-01 06:29:20.000> 31 0.186 2000-01-01 06:33:00.000
>
> 25 0.193 2000-01-01 06:29:24.000> 24 0.289 2000-01-01 06:29:00.000
>
> 26 0.299 2000-01-01 06:29:37.000
> 28 0.444 2000-01-01 06:29:56.000
> 30 0.665 2000-01-01 06:30:24.000
> Except ID 24 and ID 31(These ArrivalTime were NOT NULL), ArrivalTime
> seems prportional to Distance beween ArrivalTime of ID 24 and ID 31.
Correct. That's the point with the interpolation.

> One reason I asked this is that if ArrivalTime of some station(s)
> between ID 24 and ID 31 is NOT NULL, what is the distance of that
> station?.
> For example:
>
> > ID Distance ArrivalTime
> > 24 0.289 2000-01-01 06:29:00.000
> > 25 0.193 NULL --> 1st value to be interpolated
> > 26 0.299 NULL --> 2nd value to be interpolated
> > 27 0.131 NULL --> 3rd value to be interpolated
> > 28 0.444 NOT NULL --> value is already known
> > 29 0.160 NULL --> 4th value to be interpolated
> > 30 0.665 NULL --> 5th value to be interpolated
> > 31 0.186 2000-01-01 06:33:00.000
>
> And more important question is how to calculate middle ArrivalTime
> which is NULL.
Distance at index N is meant as the distance ran from the Index N-1 In the case ID 28 0.444 is the distance ran from the interpolated value at ID 27...
As paul c underlined, each existing value in ArrivalTme means a pair defining a new interval on which the formulas can be implemented. If ID 28 indeed existed then ID29 and ID 30 would then be interpolated from interval 28 - 31 instead of 24-31. Hope this makes sense.

I later fond out that the formula proposed is not correct but I still presented it to this NG because I think it is an interesting concept to discuss.

Regards... Received on Sun Apr 29 2007 - 20:44:56 CEST