[R] A "rude" question
pgilbert at bank-banque-canada.ca
Tue Feb 1 23:23:56 CET 2005
Spencer Graves wrote:
> Hi, Paul:
> How can I access "the package tests directory" you mentioned?
> Only one of the 52 subdirectories of "library" in my current
> installation of R 2.0.1 has a "test" folder.
The tests directory seems to get stripped when you install a package. If
you get a source package and untar it then there will be a tests
directory in many packages (it is not required).
> Spencer Graves
> Paul Gilbert wrote:
>> One point that did not get mentioned in this discussion, and I
>> believe deserves
>> much more publicity, is the impact of packages tests. The design of
>> the package
>> system allows package developers to put tests in packages, and these
>> are checked
>> regularly (see
>> These are intended to test the package functionality, but also give R
>> what is
>> perhaps the largest test suite of any statistical software (certainly
>> the most
>> quickly growing). While any single package's test will never
>> guarantee that
>> the package works perfectly, the ensemble goes a long way toward
>> that core R functionality behaves as intended. It seems unlikely to
>> me that any
>> commercial effort will ever be able to catch up.
>> There are several ways that tests can add to our confidence that
>> calculations can be trusted. They can
>> - check against theoretical results
>> - check against published results
>> - check against results from other software
>> - check that calculations done in different ways give the same result
>> - check that monte carlo experiments give distributions that are
>> with expected results
>> Some of these are relatively time consuming to set up and check the
>> first time,
>> but after that they can be automatic.
>> If you have particular calculations with specific packages that you
>> are especially
>> concerned about, I encourage you to participate by devising good
>> tests and sending
>> them to the package developers. (But first check the tests they are
>> already doing
>> in the package tests directory.)
>> Paul Gilbert
>> msck9 at mizzou.edu wrote:
>>> Dear all, I am beginner using R. I have a question about it. When
>>> you use it,
>>> since it is written by so many authors, how do you know that the
>>> results are trustable?(I don't want to affend anyone, also I trust
>>> people). But I think this should be a question.
>>> R-help at stat.math.ethz.ch mailing list
>>> PLEASE do read the posting guide!
>> R-help at stat.math.ethz.ch mailing list
>> PLEASE do read the posting guide!
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