[R] [Q] Newbie (continued.. at least I got R running allready :-)
Petr Pikal
petr.pikal at precheza.cz
Mon Jun 21 14:27:20 CEST 2004
Hi
On 18 Jun 2004 at 8:34, Gabor Grothendieck wrote:
>
>
> Check out ?turnpoints in the pastecs library.
>
> Try
>
> example(turnpoints)
> str(Nauplii.tp)
>
> to see the data structure you get back. It identifies the peaks
> and pits and other associated information.
I am not sure if this is exactly what Jeroen really wants. As I went
through the picture (BTW it could be better if it had been slightly
smaller:), it seems to me that the "peaks" are very flat. If you look
at them they are like that
*****************************
******* **
*** *
* *
* *
^ ^ ^
1 2 3
and he/she wants to know where it starts and where it ends. What I
am not sure from the picture above is, if the peak starts at point 1,
2 or 3. Function rle can be of some help in that particular case, but
it depends what they want really to extract
based on data provided
vyber <- rle(co2)$values>20 & rle(co2)$lengths>5
# gives values co2 which are bigger than 20 and which are
simultaneously repeated more than five times
rle(co2)$values[vyber]
[1] 35 36 37 32 35 35 34 32 35 36 35 35 36 37 35 37 37 35 36 37
35 35 37 30 29 36 37 37 32 25 36 38 39
# here are the values
> rle(co2)$lengths[vyber]
[1] 6 14 29 16 50 18 16 20 7 29 31 6 10 18 7 28 52 6 10 22 34
6 10 13 11 10 10 23 10 7 8 6 47
# and here is their lengths
But it can be found that e.g. first three values are from the first
peak.
So I suppose they need to look more closely on what they really
want to know and than try to code it in R.
Cheers
Petr
>
> Date: Fri, 18 Jun 2004 11:23:54 +0200
> From: jeroen clarysse <jeroen.clarysse at easynet.be>
> To: <r-help at stat.math.ethz.ch>
> Subject: [R] [Q] Newbie (continued.. at least I got R running
> allready :-)
>
>
> Hi all
>
> a week ago, I posted a newbie question in data smoothing &
> maximum-extraction with R. I got quite a lot of response, but I'm
> still kinda stuck with it...
>
> I'll restate the problem : i got a datafile with 2400 measuerements
> (every 250msec) of a CO2 measurement device, capturing the breath of a
> subject. I uploaded such a sample here :
>
> http://www.psy.kuleuven.ac.be/leerpsy/data.csv
>
> now I wish to figure out where each breath expiration ceiling takes
> place , as shown on this graph :
>
> http://www.psy.kuleuven.ac.be/leerpsy/graph.bmp
>
>
> I'm kinda stuck on how to get this running in R.
>
> I really hope someone can help me out. If you guys can get me running,
> I promise to promote R as often as I can here on our faculty (which
> still uses Statistica for almost everything)
>
> thanks a million in advance !
>
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Petr Pikal
petr.pikal at precheza.cz
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