[Rcpp-devel] broken package after udpate

[Romain Francois]

This is about one of C++ most annoying things. order of includes.

To make it short, the function that is responsible for making an R 
object out of the returned arma::mat is module_wrap, which calls wrap,

Where module_wrap is currently written, it does not "see" the wrap() 
overloads from RcpppArmadillo so it just uses a version that uses 
begin() and end() and therefor just creates a vector.

So, alright. I broke this. This is an easy fix, although I'm afraid one 
that has to happen in Rcpp.

A contingency measure might be to write your euler function like this:



SEXP euler(const double phi, const double theta, const double psi)
   {
     arma::mat Rot(3,3);
     const double cosphi = cos(phi), cospsi = cos(psi), costheta = 
cos(theta);
     const double sinphi = sin(phi), sinpsi = sin(psi), sintheta = 
sin(theta);
     Rot(0,0) = cospsi*cosphi - costheta*sinphi*sinpsi;
     Rot(0,1) = cospsi*sinphi + costheta*cosphi*sinpsi;
     Rot(0,2) = sinpsi*sintheta;

     Rot(1,0) = -sinpsi*cosphi - costheta*sinphi*cospsi;
     Rot(1,1) = -sinpsi*sinphi + costheta*cosphi*cospsi;
     Rot(1,2) = cospsi*sintheta;

     Rot(2,0) = sinphi*sintheta;
     Rot(2,1) = -cosphi*sintheta;
     Rot(2,2) = costheta;

     return wrap(Rot);
   }

because there you call the right "wrap".

Of course, the desired behaviour of having arma::mat as returned type 
will be brought back.

Romain

Le 17/11/12 00:08, Dirk Eddelbuettel a écrit :
>
> On 17 November 2012 at 11:31, baptiste auguie wrote:
> | Hi,
> |
> | (Hopefully this makes it to the list; I believe I've had problems reaching it
> | because of a recent change between @gmail and @googlemail).
>
> Looks like it.
>
> | I made a minimal package * to illustrate the problem of my recently broken
> | package cda (since yesterday's update of Rcpp). There's only one function euler
> | () in a Module named cda. It used to return a 3x3 matrix, but after updating to
> | Rcpp 0.10 it returns a vector. You can run the example with
> |
> | $ R -f inst/testing/test.r
> |
> | What am I doing wrong?
> |
> | Best,
> |
> | baptiste
> |
> | * https://dl.dropbox.com/u/352834/cda_1.2.1.tar.gz
>
> Good example. I added one line
>      Rcpp::Rcout << "In Euler, Rot is " << std::endl << Rot << std::endl;
> and the end of 'Euler' and we see that the dimension is in fact there, but
> then gets lost on the way out:
>
>
> edd at max:/tmp/baptiste$ r -lcda -p -e'M <- cda$euler(1.1, 2.0, 3.1); dim(M); class(M); M'
>   [1] "cda"           "grid"          "reshape2"      "randtoolbox"
>   [5] "rngWELL"       "statmod"       "plyr"          "RcppArmadillo"
>   [9] "Rcpp"          "methods"       "base"
> In Euler, Rot is
>    -0.4378  -0.8983   0.0378
>    -0.3894   0.1515  -0.9085
>     0.8104  -0.4125  -0.4161
>
> [1] -0.43778268 -0.38941320  0.81037256 -0.89828547  0.15154235 -0.41245379
> [7]  0.03780919 -0.90851102 -0.41614684
> NULL
> [1] "numeric"
> [1] -0.43778268 -0.38941320  0.81037256 -0.89828547  0.15154235 -0.41245379
> [7]  0.03780919 -0.90851102 -0.41614684
> edd at max:/tmp/baptiste$
>
> That is with the newest Rcpp and RcppArmadillo.  So somewhere we are loosing
> the matrix attribute.
>
> If I 'make the whole thing slower' by explicitly converting, it works -- I
> just add euler2 as
>
> NumericMatrix euler2(const double phi, const double theta, const double psi) {
>    arma::mat M(3,3);
>    M = euler(phi, theta, psi);
>    return Rcpp::wrap(M);
> }
> // [...]
> function( "euler2", &euler2, "Constructs a 3x3 Euler rotation matrix" ) ;\
>
> as seen here:
>
>
> edd at max:/tmp/baptiste$ r -lcda -p -e'M <- cda$euler2(1.1, 2.0, 3.1); dim(M); class(M); M'
>   [1] "cda"           "grid"          "reshape2"      "randtoolbox"
>   [5] "rngWELL"       "statmod"       "plyr"          "RcppArmadillo"
>   [9] "Rcpp"          "methods"       "base"
> In Euler, Rot is
>    -0.4378  -0.8983   0.0378
>    -0.3894   0.1515  -0.9085
>     0.8104  -0.4125  -0.4161
>
>             [,1]       [,2]        [,3]
> [1,] -0.4377827 -0.8982855  0.03780919
> [2,] -0.3894132  0.1515423 -0.90851102
> [3,]  0.8103726 -0.4124538 -0.41614684
> [1] 3 3
> [1] "matrix"
>             [,1]       [,2]        [,3]
> [1,] -0.4377827 -0.8982855  0.03780919
> [2,] -0.3894132  0.1515423 -0.90851102
> [3,]  0.8103726 -0.4124538 -0.41614684
> edd at max:/tmp/baptiste$
>
> So somewhere between the compiler getting smarter, Conrad optimising
> expression and us, an attribute got lost.
>
> Maybe Romain can find a way to make this explicit.
>
> Cheers, Dirk
>
>
>


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Romain Francois
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