**Subject: **Strange 'Unimplemented feature in rep' error (PR#254)

*prechelt@ira.uka.de*

**Date: **Tue 24 Aug 1999 - 04:27:00 EST

**Next message:**maechler@stat.math.ethz.ch: "Re: Error in ?text (PR#256)"**Previous message:**Prof Brian D Ripley: "Re: Strange 'Unimplemented feature in rep' error (PR#254)"**Next in thread:**Prof Brian D Ripley: "Re: Strange 'Unimplemented feature in rep' error (PR#254)"

Message-Id: <199908231827.UAA15353@pubhealth.ku.dk>

I have a large computation that performs various bootstrap resampling

loops over pairs of samples using lapply().

After a few seconds it stops like this

*> do.summarize.effects(compute.power=T)
*

...

Error: Unimplemented feature in rep

*> .Traceback
*

[[1]]

[1] "rep(no, length = length(ans))"

[[2]]

[1] "ifelse(t.howto == \"n\", boot.result, l.meanboot.test(onew.x, onew.y, " " samples = boot.test.samples, expect = makezero, return.htest = T, "

[3] " alt = \"t\"))"

[[3]]

[1] "measure.power(firstset, secondset, t.howto = t.howto, var.equal = var.equal)"

[[4]]

[1] "FUN(X[[i]], ...)"

[[5]]

[1] "lapply(split(X, group), FUN, ...)"

[[6]]

[1] "tapply(1:nrow(dd), grouping, summarize.effects, compute.power = compute.power)"

[[7]]

[1] "as.list(X)"

[[8]]

[1] "lapply(as.list(X), FUN, ...)"

[[9]]

[1] "sapply(tapply(1:nrow(dd), grouping, summarize.effects, compute.power = compute.power), " " rbind)"

[[10]]

[1] "t(sapply(tapply(1:nrow(dd), grouping, summarize.effects, compute.power = compute.power), " " rbind))"

[[11]]

[1] "do.summarize.effects(compute.power = T)"

My problems are the following:

1. I cannot find the line

rep(no, length = length(ans))

anywhere in my own code

2. The R source code of 'rep' does not contain the error message

"unimplemented feature" (I have not checked the .Internal)

3. I've had similar strange errors before and could not find the problem

in my own code. The problem finally went away after I renamed two

of the groups in my data such that the factor ordering changed and

the computations were performed in a different order...

4. I've also previously had the effect that my function that reads the data

using read.table(), which is not part of the above call,

reproducibly came up with the second column being NULL instead

of 1451 items as the other colums. A second call to the same function

reliably came back with the correct result. I am not sure whether

these problems are related but I think both were not my fault.

Any suggestions where to look for the above problem?

Both my data and my computations are somewhat lengthy so the

stepwise-stripping-down approach is cumbersome.

The new problem appeared using the same data as in (3) above, but

after some extensions to the code (none of them introducing a new

call to rep()).

The problem does also appear if I use only the small subset of the

data used in the respective part of the computation that fails.

Thanks in advance for your help

Lutz

Lutz Prechelt http://wwwipd.ira.uka.de/~prechelt/ | Whenever you

Institut f. Programmstrukturen und Datenorganisation | complicate things,

Universitaet Karlsruhe; D-76128 Karlsruhe; Germany | they get

(Phone: +49/721/608-4068, FAX: +49/721/608-7343) | less simple.

*>>> Ever had negative research results? http://wwwipd.ira.uka.de/fnr <<<
*

--please do not edit the information below--

Version:

platform = alpha-dec-osf4.0

arch = alpha

os = osf4.0

system = alpha, osf4.0

status =

status.rev = 0

major = 0

minor = 64.1

year = 1999

month = May

day = 8

language = R

Search Path:

.GlobalEnv, Autoloads, package:base

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**Next message:**maechler@stat.math.ethz.ch: "Re: Error in ?text (PR#256)"**Previous message:**Prof Brian D Ripley: "Re: Strange 'Unimplemented feature in rep' error (PR#254)"**Next in thread:**Prof Brian D Ripley: "Re: Strange 'Unimplemented feature in rep' error (PR#254)"

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