[R-pkg-devel] Checking the number of cores used

[Duncan Murdoch]

Sorry, I missed the --as-cran option:  you run

  R CMD check --as-cran <pkg>

Duncan Murdoch

On 19/09/2023 5:59 a.m., Duncan Murdoch wrote:
> On 18/09/2023 10:10 a.m., Shu Fai Cheung wrote:
>> Hi All,
>>
>> I know we should not use more than 2 cores in tests, vignettes, etc. I
>> encountered and solved this issue before. However, I still committed
>> this mistake in a new package and would like find out where the cause
>> is.
>>
>> I have a package that already has parallel processing disabled by
>> default and I did not enable parallel processing in the examples and
>> tests (except for one test, which is always skipped by skip()).
>> However, I was told that somewhere in the package more than 2 cores
>> are used.
>>
>> I checked several times and even added a temporary 'stop()` to "trap"
>> parallel processing but still could not find where the source of the
>> problem is.
>>
>> I checked the timing in the log in R CMD check results from winbuilder
>> but everything seems OK. The user time and elapsed time are similar
>> for all the examples.
>>
>> Is there any quick way to check where things go wrong regarding the
>> number of cores? It is not easy to find the source of the problems
>> when there are many examples and tests.
> 
> If you run R CMD check <pkg> at the command line, it will produce a
> directory *.Rcheck containing a number of files.  One of those files
> will be *-Ex.timings, which will give the individual timings of each of
> the examples in your package.  Maybe you can recognize from those which
> of the examples are problematic ones, and add `proc.time()` calls to the
> example to figure out which line(s) cause the issue.
> 
> I don't remember whether winbuilder keeps the timings file when it runs
> a check.
> 
> Duncan Murdoch
>