Hi Dirk,
yes I am familiar with new style (thank you for that, it makes things much
prettier), but I still have to (or do I?...) use the as<>() when I am picking
the pieces out of Rcpp::List
(https://github.com/helske/bssm/blob/master/src/gssm.cpp):
....
gssm::gssm(const List model, unsigned int seed) :
y(as<arma::vec>(model["y"])), Z(as<arma::mat>(model["Z"])),
H(as<arma::vec>(model["H"])), T(as<arma::cube>(model["T"])), ...
I don't want to modify objects on the R side, so I had to use clone for the
List model. I was just wondering why the behaviour is different for cube (tries
to avoid a copy) than for vec/mat when using as<>() (always? forces a copy).
Jouni
________________________________________
Lähettäjä: Dirk Eddelbuettel [e...@debian.org]
Lähetetty: 22. syyskuuta 2016 23:09
Vastaanottaja: Dirk Eddelbuettel
Kopio: Helske, Jouni; rcpp-devel@lists.r-forge.r-project.org
Aihe: Re: [Rcpp-devel] Initializing Armadillo vec/cube from NumericVector using
as conversion
Oh, and it should work the same for cube types:
R> cppFunction("void test2(arma::cube & x) { x(0,0,0) = 0.5; }",
R> depends="RcppArmadillo")
R> v <- array(sqrt(1:8), c(2, 2, 2))
R> v
, , 1
[,1] [,2]
[1,] 1.00000 1.73205
[2,] 1.41421 2.00000
, , 2
[,1] [,2]
[1,] 2.23607 2.64575
[2,] 2.44949 2.82843
R> test2(v)
R> v
, , 1
[,1] [,2]
[1,] 0.50000 1.73205
[2,] 1.41421 2.00000
, , 2
[,1] [,2]
[1,] 2.23607 2.64575
[2,] 2.44949 2.82843
R>
Proxy object that still connected to the outside object, unless a cast is
needed (int <-> double), or a copy is enforced (clone(), possibly via as<>()).
Dirk
--
http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org
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