I'm trying to use a self-written function with the summaryBy function (doBy
package).
I have lots of data from Monte Carlo experiments comparing different
estimators across different (combinations of) parameter values, similar to
the following form:
colnames(mydata) <- c("X", "b0", "b1", #
parameter combination,
corresponding (true) parameter values
"b0.m1", "b1.m1", # estimates for estimator 1
"b0.m2", "b1.m2" # estimates for estimator 2)
Thus, X is an id that is constant for a given parameter combination across
simulation runs.
I need to calculate the root mean squared error. For each estimate I extract
the corresponding parameter value from the column name of the estimates:
rmse <- function(est){
parname <- deparse(substitute(est))
par1 <- unlist(strsplit(parname, c("\\.")))[1]
par2 <- eval(parse(text=par1))
sqrt(sum((par2- est)^2) /length(est))
}
This works well for subsets (i.e. given parameter combinations), but not
inside the summaryBy function because I cannot index properly.
data1 <- subset(mydata, X==1)
rmse(data1$b0.m1)
summaryBy(b0.m5 X, data=mydata, FUN=c(mean, rmse))
I would need to be able to index inside the rmse function, i.e. something
like:
sqrt(sum((par2[X==i]- est)^2) /length(est))
How can I fix this?
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