Thanks Josh,
I appreciate your comments. Merge is quite easy and I guess I should just go
that route. I don't have so many data points so the speed isn't really much
of an issue. I was just curious whether there was anything more elegant.
Yes, the function is not clear or ideal for troubleshooting. I adapted this
from an excel sheet in an effort to speed my data analysis and in the excel
file the final calculation was simply a long string of calculations. I
appreciate your attempt to make it clearer and to chunk it into fewer easier
to read pieces. I plan to go back and do that as well.
Thanks again.
Nate
On Wed, Oct 19, 2011 at 10:33 PM, Joshua Wiley <jwiley.ps...@gmail.com>wrote:
> Hi Nathan,
>
> I honestly do not think that anything else will be much better than
> merging the two datasets. If the datasets are not merged, you
> essentially have to apply your optode function to each vial, store the
> results, then combine them all together. This is innefficient.
> Merging the datasets may be innefficient in a way, but once it is
> done, your function can be applied to the entire dataset in one step.
> If you have big data and the merge is slow, take a look at the
> data.table package. I have recently (not that it was bad before, I
> just never really knew how much it could do) been quite impressed with
> it. As a whole other note, your optode function was quite difficult
> to read, and I highly doubt you can confidently look at the code and
> ensure there is not a typo, missed operator, etc. somewhere in that
> block of formula code. I attempted to clean it up some, though
> perhaps not with 100% success.
>
> #######################################
> optode2 <- function(cal0, T0, cal100, T100, phase, temp) {
> dr <- pi/180
> f1 <- 0.801
> deltaPsiK <- (-0.08)
> deltaKsvK <- 0.000383
> m <- 22.9
> tan0T100 <- tan(((cal0 + deltaPsiK * (T100 - T0))) * dr)
> tan0Tm <- tan((cal0 + (deltaPsiK * (temp - T0))) * dr)
> tan100T100 <- tan(cal100 * dr)
> tanmTm <- tan(phase * dr)
> A <- tan100T100 / tan0T100 / m * 100^2
>
> B <- tan100T100 / tan0T100 * 100 + tan100T100 / tan0T100 / m *100 -
> f1 / m * 100 - 100 + f1 * 100
> C <- tan100T100 / tan0T100 - 1
> KsvT100 <- (- B + (sqrt(B^2 - 4 * A * C))) / (2 * A)
> KsvTm <- KsvT100 + (deltaKsvK * (temp - T100))
> a <- tanmTm / tan0Tm / m * KsvTm^2
> b <- tanmTm / tan0Tm * KsvTm + tanmTm / tan0Tm / m * KsvTm - f1 / m
> * KsvTm - KsvTm + f1 * KsvTm
> c <- tanmTm / tan0Tm - 1
> tot <- tanmTm / tan0T100
> big <- tot * KsvTm + tanmTm / tan0T100 / m * KsvTm - f1 / m * KsvTm
> - KsvTm + f1 * KsvTm
>
> saturation <- (-big + (sqrt((big)^2-4 * (tanmTm / tan0T100 / m *
> KsvTm^2) * (tot - 1)))) / (2 * (tot / m * KsvTm^2))
> return(saturation)
> }
>
> ## Read in your example data
> d1 <- read.table(textConnection("
> vial cal0 T0 cal100 T100
> 1 61 18 28 18
> 2 60.8 18 27.1 18
> 3 60.2 18 28.3 18
> 4 59.8 18 27.2 18"), header = TRUE, stringsAsFactors =
> FALSE)
> d2 <- read.table(textConnection("
> vial phase temp time
> 1 31 17.5 10
> 1 31.5 17.4 20
> 1 32.8 17.5 30
> 2 29.0 17.5 10
> 2 29.7 17.5 20
> 2 30.9 17.5 30
> 3 27.1 17.4 10
> 3 27.6 17.4 20
> 3 28.1 17.5 30
> 4 31.0 17.6 10
> 4 33.3 17.6 20
> 4 35.6 17.6 30"), header = TRUE, stringsAsFactors =
> FALSE)
> closeAllConnections()
>
> dat <- merge(d1, d2, by = "vial")
> ## optode wrapper
> f <- function(d) optode2(d$cal0, d$T0, d$cal100, d$T100, d$phase, d$temp)
>
> dat$oxygen <- f(dat)
>
> dat
> #######################################
>
>
> Cheers,
>
> Josh
>
> On Wed, Oct 19, 2011 at 8:38 PM, Nathan Miller <natemille...@gmail.com>
> wrote:
> > Hello,
> >
> > I am not entirely sure the subject line captures what I am trying to do,
> but
> > hopefully this description of the problem will help folks to see my
> > challenge and hopefully offer constructive assistance.
> >
> > I have an experimental setup where I measure the decrease in oxygen in
> small
> > vials as an organism, such as an oyster, consumes the oxygen. Each vial
> is
> > calibrated before the experiment and these calibrations are used to
> convert
> > the raw data after the experiment into oxygen values. I end up with two
> > dataframes. One has the calibration data and for example could look like
> > this
> >
> > vial cal0 T0 cal100 T100
> > 1 61 18 28 18
> > 2 60.8 18 27.1 18
> > 3 60.2 18 28.3 18
> > 4 59.8 18 27.2 18
> >
> > The second is a data file which could look like this
> >
> >
> > vial phase temp time
> > 1 31 17.5 10
> > 1 31.5 17.4 20
> > 1 32.8 17.5 30
> > 2 29.0 17.5 10
> > 2 29.7 17.5 20
> > 2 30.9 17.5 30
> > 3 27.1 17.4 10
> > 3 27.6 17.4 20
> > 3 28.1 17.5 30
> > 4 31.0 17.6 10
> > 4 33.3 17.6 20
> > 4 35.6 17.6 30
> >
> > I have a complicated function (included at the bottom) that uses the
> > calibration values and the raw data to calculate actual oxygen levels. It
> > works great, but as its currently written it requires that each
> calibration
> > be entered individually. I would rather apply the function based upon the
> > vial number (applying the calibration for vial 1 to all vial 1 data,
> > calibration for vial 2 to all vial 2 data).
> >
> > I have managed to do this by combining the two dataframes into one that
> > looks like this
> >
> > data
> > vial phase temp time cal0 T0 cal100 T100
> > 1 31 17.5 10 61 18 28 18
> > 1 31.5 17.4 20 61 18 28 18
> > 1 32.8 17.5 30 61 18 28 18
> > 1 33.6 17.5 40 61 18 28 18
> > 2 29.0 17.5 10 60.8 18 27.1 18
> > 2 29.7 17.5 20 60.8 18 27.1 18
> > 2 30.9 17.5 30 60.8 18 27.1 18
> > 3 27.1 17.4 10 60.2 18 28.3 18
> > 3 27.6 17.4 20 60.2 18 28.3 18
> > 3 28.1 17.5 30 60.2 18 28.3 18
> > 4 31.0 17.6 10 59.8 18 27.2 18
> > 4 33.3 17.6 20 59.8 18 27.2 18
> > 4 35.6 17.6 30 59.8 18 27.2 18
> >
> > I have then used ddply to apply my function grouped by "vial"
> >
> > oxygen<-ddply(data,.(vial), function(d) optode(d$cal0, d$T0, d$cal100,
> > d$T100, d$phase, d$temp))
> >
> > This works, but I do not like having to put the calibrations into the
> same
> > dataframe as the data. Can anyone show me an example of how I could have
> a
> > function reference a dataframe (like the calibration data) based upon a
> > grouping variable (like "vial") and use that data as partial inputs to
> the
> > function when it is applied to another dataframe (the actual data)? I
> don't
> > necessarily need an example using my sample data or the function I have
> > included here (as it is rather unwieldly). A simplified example of how to
> > achieve this type of cross referencing would suffice and I can apply the
> > principle to my current problem.
> >
> > Thanks so much,
> > Nate
> >
> >
> > optode<-function(cal0,T0,cal100,T100,phase,temp) {
> >
> > f1=0.801
> > deltaPsiK=-0.08
> > deltaKsvK=0.000383
> > m=22.9
> > tan0T100=tan(((cal0+deltaPsiK*(T100-T0)))*pi/180)
> > tan0Tm=tan((cal0+(deltaPsiK*(temp-T0)))*pi/180)
> > tan100T100=tan(cal100*pi/180)
> > tanmTm=tan(phase*pi/180)
> > A=tan100T100/tan0T100*1/m*100^2
> >
> >
> B=tan100T100/tan0T100*100+tan100T100/tan0T100*1/m*100-f1*1/m*100-100+f1*100
> > C=tan100T100/tan0T100-1
> > KsvT100=(-B+(sqrt(B^2-4*A*C)))/(2*A)
> > KsvTm=KsvT100+(deltaKsvK*(temp-T100))
> > a=tanmTm/tan0Tm*1/m*KsvTm^2
> >
> > b=tanmTm/tan0Tm*KsvTm+tanmTm/tan0Tm*1/m*KsvTm-f1*1/m*KsvTm-KsvTm+f1*KsvTm
> > c=tanmTm/tan0Tm-1
> >
> >
> saturation=(-((tan(phase*pi/180))/(tan((cal0+(deltaPsiK*(temp-T0)))*pi/180))*(KsvT100+(deltaKsvK*(temp-T100)))+(tan(phase*pi/180))/(tan((cal0+(deltaPsiK*(temp-T0)))*pi/180))*1/m*(KsvT100+(deltaKsvK*(temp-T100)))-f1*1/m*(KsvT100+(deltaKsvK*(temp-T100)))-(KsvT100+(deltaKsvK*(temp-T100)))+f1*(KsvT100+(deltaKsvK*(temp-T100))))+(sqrt((((tan(phase*pi/180))/(tan((cal0+(deltaPsiK*(temp-T0)))*pi/180))*(KsvT100+(deltaKsvK*(temp-T100)))+(tan(phase*pi/180))/(tan((cal0+(deltaPsiK*(temp-T0)))*pi/180))*1/m*(KsvT100+(deltaKsvK*(temp-T100)))-f1*1/m*(KsvT100+(deltaKsvK*(temp-T100)))-(KsvT100+(deltaKsvK*(temp-T100)))+f1*(KsvT100+(deltaKsvK*(temp-T100)))))^2-4*((tan(phase*pi/180))/(tan((cal0+(deltaPsiK*(temp-T0)))*pi/180))*1/m*(KsvT100+(deltaKsvK*(temp-T100)))^2)*((tan(phase*pi/180))/(tan((cal0+(deltaPsiK*(temp-T0)))*pi/180))-1))))/(2*((tan(phase*pi/180))/(tan((cal0+(deltaPsiK*(temp-T0)))*pi/180))*1/m*(KsvT100+(deltaKsvK*(temp-T100)))^2))
> >
> > print(saturation)
> >
> > }
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
>
>
> --
> Joshua Wiley
> Ph.D. Student, Health Psychology
> Programmer Analyst II, ATS Statistical Consulting Group
> University of California, Los Angeles
> https://joshuawiley.com/
>
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