[R-pkg-devel] R_orderVector1 - algo: radix, shell, or another?

[Simon Urbanek]

I think the logic Jeff had in mind is that R order() uses C do_order() for method="shell" and since do_order() uses orderVector1() by induction it is the shell-sort implementation.

order() itself uses whatever you specify in method=.

Cheers,
Simon


> On Sep 25, 2023, at 7:10 AM, Jan Gorecki <j.gorecki using wit.edu.pl> wrote:
> 
> Hi Jeff,
> 
> Yes I did. My question is about R_orderVector1 which is part of public R C
> api.
> Should I notice something relevant in the source of R's order?
> 
> Best
> Jan
> 
> On Sun, Sep 24, 2023, 17:27 Jeff Newmiller <jdnewmil using dcn.davis.ca.us> wrote:
> 
>> Have you read the output of
>> 
>> order
>> 
>> entered at the R console?
>> 
>> 
>> On September 24, 2023 1:38:41 AM PDT, Jan Gorecki <j.gorecki using wit.edu.pl>
>> wrote:
>>> Dear pkg developers,
>>> 
>>> Are there any ways to check which sorting algorithm is being used when
>>> calling `order` function? Documentation at
>>> https://stat.ethz.ch/R-manual/R-devel/library/base/html/sort.html
>>> says it is radix for length < 2^31
>>> 
>>> On the other hand, I am using R_orderVector1, passing in double float
>>> smaller than 2^31. Short description of it states
>>> "Fast version of 1-argument case of R_orderVector".
>>> Should I expect R_orderVector1 follow the same algo as R's order()? If so
>>> it should be radix as well.
>>> 
>>> 
>> https://github.com/wch/r-source/blob/ed51d34ec195b89462a8531b9ef30b7b72e47204/src/main/sort.c#L1133
>>> 
>>> If there is no way to check sorting algo, could anyone describe which one
>>> R_orderVector1 uses, and if there is easy API to use different ones from
>> C?
>>> 
>>> Best Regards,
>>> Jan Gorecki
>>> 
>>>      [[alternative HTML version deleted]]
>>> 
>>> ______________________________________________
>>> R-package-devel using r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-package-devel
>> 
>> --
>> Sent from my phone. Please excuse my brevity.
>> 
> 
> 	[[alternative HTML version deleted]]
> 
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