R help - Dec 2017 - Rcpp, dyn.load and C++ problems

On 3 December 2017 at 05:23, Eric Berger <ericjberger at gmail.com> wrote:
>
> Do a search on "Rcpp calling C++ functions from R"
>
Thanks. However search for "Rcpp calling C++ functions from R" gives a
lot
of result but I think
some of them are outdated and others don't agree with each other.

Can you point to a specific good on-line guide for me?

Regards
Martin

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I would go to the source, in this case Dirk Eddelbuettel's (I hope I
spelled it correctly) documentation for Rcpp:

http://dirk.eddelbuettel.com/code/rcpp/Rcpp-attributes.pdf

Note that you need to do

sourceCpp("logistic_map.cpp")

in R instead of building and dyn.load()-ing the object.

HTH,

Peter

On Sun, Dec 3, 2017 at 11:04 AM, Martin M?ller Skarbiniks Pedersen
<traxplayer at gmail.com> wrote:
> On 3 December 2017 at 05:23, Eric Berger <ericjberger at gmail.com>
wrote:
>
>>
>> Do a search on "Rcpp calling C++ functions from R"
>>
>
> Thanks. However search for "Rcpp calling C++ functions from R"
gives a lot
> of result but I think
> some of them are outdated and others don't agree with each other.
>
> Can you point to a specific good on-line guide for me?
>
> Regards
> Martin
>
>         [[alternative HTML version deleted]]
>
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On 3 December 2017 at 11:08, Peter Langfelder wrote:
| I would go to the source, in this case Dirk Eddelbuettel's (I hope I
| spelled it correctly)

You did. Take a point :)

| documentation for Rcpp:
| 
| http://dirk.eddelbuettel.com/code/rcpp/Rcpp-attributes.pdf

Yup.  And

    RShowDoc("Rcpp-attributes", package="Rcpp")

in R is even easier.

On 3 December 2017 at 13:19, Dirk Eddelbuettel wrote:
| 0) Wrong list. Rcpp has its down, rcpp-devel, and I basically do not read
| this and would have missed this were it not for luck.

"R has its own list, rcpp-devel" is what I meant to write.  For
completeness,
we can also test on the command-line as Martin and what I do a lot myself:

edd at bud:~$ r -lRcpp -e'sourceCpp("/tmp/mmsp.cpp")'

R> res <- compute_values_cpp()

R> str(res)

Attaching package: ?utils?

The following objects are masked from ?package:Rcpp?:

    .DollarNames, prompt

List of 2
 $ x: num [1:100000] 199 362 118 302 262 ...
 $ y: num [1:100000] 20 40 14.3 39.5 36.9 ...
You have mail in /var/mail/edd
edd at bud:~$


That uses littler which I like, Rscript is almost the same (but has no -l
switch for libraries and fails to load the methods package which we sometimes
need).

Dirk


-- 
http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org