[Rcpp-devel] variable affectation in Rcpp Rcpp Armadillo

[Nicolas Heslot]

I ran into the same kind of problem again, but this time I just can't find
what the correct syntax is:
I need to update a matrix stored in a list, by summing with an arma:: mat
object
the syntax MyList[j]  += ArmaObject does not work.
On the other hand I can access the matrix object stored in those list and
use them as arma::mat.
I tried various syntax using wrap or as but I can't get it working.
The error message is:
error: no match for 'operator+=' in 'Rcpp::Vector<RTYPE>::operator[](int)
[with int RTYPE = 19, Rcpp::Vector<RTYPE>::Proxy =
Rcpp::internal::generic_proxy<19>](k) += arma::operator-(const
arma::Base<typename T1::elem_type, T1>&, const arma::Base<typename
T1::elem_type, T2>&) [with T1 = arma::Glue<arma::eOp<arma::subview<double>,
arma::eop_sc

And the full inline code is:

## loop code
src <- '
// n markers
int P = as<int>(P_);
// n individuals
int N = as<int>(N_);
// marker polynome degree
int degM = as<int>(degM_);
// variance
//int sigma2 = as<int>(sigma2_);
//Rcpp::NumericVector sigma2(sigma2_);
double sigma2 = as<double>(sigma2_);
// design matrix
arma::mat gen_a = Rcpp::as<arma::mat>(gen_a_);
// covariate X
arma::mat X = Rcpp::as<arma::mat>(X_);
// alpha
arma::mat alpha = Rcpp::as<arma::mat>(alpha_);
// mu
arma::mat mu = Rcpp::as<arma::mat>(mu_);
// a_old
arma::mat a_old = Rcpp::as<arma::mat>(a_old_);
// tau2
arma::mat tau2 = Rcpp::as<arma::mat>(tau2_);
// list
List all_ui = as<List>(all_ui_);
List all_ui2 = as<List>(all_ui2_);
List all_ui3 = as<List>(all_ui3_);
List all_corMat = as<List>(all_corMat_);
List all_rd = as<List>(all_rd_);
arma::mat tmp;
arma::mat tmp2 = arma::zeros<arma::mat>((degM+1),(degM+1));
arma::mat tmp3 = arma::zeros<arma::mat>(1,(degM+1));
arma::mat ui;
arma::mat ui2;
arma::mat ui3;
arma::mat sig;
arma::mat sigma;
arma::mat sigma3;
arma::mat rdi;
arma::mat all_corMati;
arma::mat diag;
arma::mat diag2 = arma::zeros<arma::mat>((degM+1),(degM+1));
arma::mat sol;
arma::mat aVar_j;
arma::mat aMu_j;
int n = 1;
int p = 0;
arma::mat U;
arma::vec s;
arma::mat V;
arma::mat rdn;
arma::mat ans;
arma::mat vsqrt;
arma::mat a = arma::zeros<arma::mat>(P,(degM+1));
List test(N);
        for (int j = 0; j < P; j++) {
        tmp2.fill(0);
        tmp3.fill(0);
              for (int i = 0; i < N; i++) {
              ui = Rcpp::as<arma::mat>(all_ui[i]);
              ui2 = Rcpp::as<arma::mat>(all_ui2[i]);
              ui3 = Rcpp::as<arma::mat>(all_ui3[i]);
              rdi = Rcpp::as<arma::mat>(all_rd[i]);
              all_corMati = Rcpp::as<arma::mat>(all_corMat[i]);
              sigma = sigma2*all_corMati;
              // calculate mean and variance
              sigma3 = sigma;
              diag=diagmat(sigma3.fill(1));
              tmp = (solve(sigma,diag)* gen_a(i,j))*ui3;
              tmp2 += (gen_a(i,j)*trans(ui))*tmp;
              tmp3 += (rdi - mu*trans(ui3)-(X(i)*alpha)*trans(ui2) +
gen_a(i,j)*a.row(j)*trans(ui))*tmp;
              };
        sol = 1/sigma2 *diagmat(diag2.fill(1/tau2(j)))+tmp2;
        aVar_j= solve(sol,diagmat(diag2.fill(1)) );
        aMu_j = aVar_j*trans(tmp3);
        ///////
        p = aVar_j.n_cols;
        svd(U,s,V,aVar_j);
        vsqrt = trans(V*(trans(U)%repmat(trans(sqrt(trans(s))),1,p)));
        rdn.randn(n,p);
        ans =rdn*vsqrt + trans(repmat(aMu_j,1,n));
        a.row(j) = ans;
              for (int k = 0; k < N; k++) {
              int k=1;
              ui = Rcpp::as<arma::mat>(all_ui[k]);
//////////////////////// Here is the issue!
              all_rd[k] += gen_a(k,j)*a_old.row(j)*trans(ui)-
gen_a(k,j)*a.row(j)*trans(ui);
              };
        };
return Rcpp::List::create(wrap(a),wrap(all_rd));'
####
fun <- cxxfunction(signature(P_ = "integer",N_ = "integer",degM_ =
"integer", sigma2_ = "double", gen_a_="matrix", X_="matrix",alpha_="matrix",
 mu_="matrix", a_old_="matrix",tau2_="matrix", all_ui_="List",
all_ui2_="List", all_ui3_="List", all_corMat_="List",
all_rd_="List"),body=src,plugin="RcppArmadillo")

Thank you very much for your help

Nicolas


On Wed, Jun 15, 2011 at 11:57 PM, Nicolas Heslot <nh269 at cornell.edu> wrote:

> I finally figured out, it was a syntax error, as the new assigned object
> was not an arma:: mat but an element from a list
> I took care of the problem by using ui = Rcpp::as<arma::mat>(all_ui[i]) in
> the reaffectation
>
> Thank you again all for your help
>
>
> On Wed, Jun 15, 2011 at 11:00 PM, Dirk Eddelbuettel <edd at debian.org>wrote:
>
>>
>> On 15 June 2011 at 20:17, Nicolas Heslot wrote:
>> | Any idea about this variable reaffectation thing?
>>
>> Well ... that still make little sense. Variables are not protected; there
>> is
>> nothing stopping you from re-assigning values, be it element-wise, row or
>> column-wise, or as a whole matrix. So I suspect you have a simple syntax
>> error.
>>
>> But as you still have not shown an actualy error it remains idle
>> speculation
>> on our side.
>>
>> | It seems to be specific to arma classes like arma::mat
>>
>> Not really. We all use these and read values from / assign values into at
>> will.  There are numerous examples in the archives of this mailing list,
>> in
>> the unit tests, and in some of the slides from past presentations.
>>
>> Dirk
>>
>> --
>> Gauss once played himself in a zero-sum game and won $50.
>>                      -- #11 at http://www.gaussfacts.com
>>
>
>
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