[R] Discriminating between experiments with xyplot (lattice)

[Deepayan Sarkar]

Here's one possibility:


d <- make.groups(v1,v2,v3)

## create interaction dropping unused levels
d$intg <- with(d, which:factor(temp))[, drop=TRUE]

## extract experiment and temp information from levels
intg.expt <- sapply(strsplit(levels(d$intg), ":", fixed = TRUE), "[[", 1)
intg.temp <- sapply(strsplit(levels(d$intg), ":", fixed = TRUE), "[[", 2)

## find a suitable color vector (where colors are repeated when the
## temperature is)
temp.unique <- unique(intg.temp)
col.temp <-
    rep(trellis.par.get("superpose.symbol")$col,
        length = length(temp.unique))
col.intg <- col.temp[match(intg.temp, temp.unique)]


xyplot(conversion ~ time, data = d, groups = intg,
       intg.expt = intg.expt,
       panel = panel.superpose,
       panel.groups = function(x, y, ..., group.number, intg.expt) {
           panel.xyplot(x, y, ...)
           panel.text(tail(x, 1), tail(y, 1), intg.expt[group.number], pos = 4)
       },
       col = col.intg,
       key = list(text = list(temp.unique), points = list(col =
col.temp, pch = 1)))


Hope that helps,

Deepayan


On 3/16/07, Frank Sarfert <CFSarfert at web.de> wrote:
> Hi Deepayan,
>
> many thanks for your quick reply.
> I actually cannot condition whith the experiment number, because in my real life data, I would like to condition with pressure and I have many more experiments (not just 3). So ideally, I would have a plot with a label near the end point of the curve which says which experiment it comes from.  So, if you could really write  some code  -  that'd be great! Many thanks in advance!
>
> Best regards
>                         Frank
>
>
> -----Ursprüngliche Nachricht-----
> Von: "Deepayan Sarkar" <deepayan.sarkar at gmail.com>
> Gesendet: 16.03.07 22:47:47
> An: "Christel u. Frank Sarfert" <cfsarfert at web.de>
> CC: r-help at stat.math.ethz.ch
> Betreff: Re: [R] Discriminating between experiments with xyplot (lattice)
>
>
> On 3/16/07, Christel u. Frank Sarfert <cfsarfert at web.de> wrote:
> > Hi,
> >
> > suppose I have data from 3 experiments which show conversion as a function of
> > time for different boundary conditions, e.g. pressure, temperature. I want to
> > plot all experiments as conversion over time grouped according to the
> > temperature. However, since I have more than one experiment performed at the
> > same temperature (but different pressures) I end up figuring out which curve
> > belongs to which experiment. (An example with artificial data of the
> > structure I use is given below. It shows three experiments where two
> > experiments at temp = 250 but press = 1 and press = 0.5 are plotted within
> > one group.)
> > My question is: Is there a way to identify which curve whithin the same group
> > belongs to which experiment, e.g by plotting a label like the experiment
> > number to the end point, or by choosing different symbols for the different
> > experiments - while keeping the color encoding of the groups?
> >
> > Your help is greatly appreciated!
> >
> > Best regards
> >                       Frank
> >
> >
> > require(lattice)
> >
> > ## generating the data, I need
> > time <- seq(0,50,1)
> > conversion <- 2 * log(time + 1)
> > press <- rep(1,51)
> > temp <- rep(250,51)
> > experiment <- rep(1, 51)
> > v1 = as.data.frame(cbind(experiment,time,conversion,press,temp))
> >
> > conversion <- 2.5 * log(time + 1)
> > press <- rep(1, 51)
> > temp <- rep(270,51)
> > experiment <- rep(2, 51)
> > v2 = as.data.frame(cbind(experiment,time,conversion,press,temp))
> >
> > conversion <- 1.25 * log(time + 1)
> > press <- rep(0.5, 51)
> > temp <- rep(250,51)
> > experiment <- rep(3, 51)
> > v3 = as.data.frame(cbind(experiment,time,conversion,press,temp))
> >
> > d <- rbind(v1,v2,v3)
>
> You want to use make.groups rather than rbind here, so that you retain
> information on which experiment each row is coming from:
>
> > dd <- make.groups(v1,v2,v3)
> > str(dd)
> 'data.frame':   153 obs. of  6 variables:
>  $ experiment: num  1 1 1 1 1 1 1 1 1 1 ...
>  $ time      : num  0 1 2 3 4 5 6 7 8 9 ...
>  $ conversion: num  0.00 1.39 2.20 2.77 3.22 ...
>  $ press     : num  1 1 1 1 1 1 1 1 1 1 ...
>  $ temp      : num  250 250 250 250 250 250 250 250 250 250 ...
>  $ which     : Factor w/ 3 levels "v1","v2","v3": 1 1 1 1 1 1 1 1 1 1 ...
>
> Now how you choose to plot this is up to you. One simple possibility
> is to create a new factor encoding both experiment and temperature,
> e.g.,
>
> xyplot(conversion ~ time, data = dd,
>           groups = (which:factor(temp))[,drop=TRUE],
>           auto.key = T)
>
> Another is to condition on one, e.g.,
>
> xyplot(conversion ~ time | factor(temp), data = dd, groups = which,
> auto.key = T)
>
> It is possible to use one one variable for color and another for
> plotting character, but the code involved would be somewhat less
> elegant (mostly because the support functions are not already built
> in). Let me know if you really want that; I can come up with some
> sample code.
>
> -Deepayan
>
>
>
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