Fix dim problem with arma::field inputs

inst/include/RcppArmadilloAs.h

@@ -30,12 +30,29 @@ namespace traits {
     class Exporter< arma::field<T> > {
     public:
         Exporter(SEXP x) : data(x){}
-
         inline arma::field<T> get() {
-            size_t n = data.size() ;
-            arma::field<T> out( n ) ;
-            for(size_t i=0; i<n; i++){
-                out[i] = as<T>(data[i]) ;
+            size_t n = data.size();
+            arma::field<T> out(n);
+            # if defined(RCPP_ARMADILLO_FIX_FieldExporter)
+                if(!Rf_isNull(data.attr("dim"))){
+                    arma::ivec dims = data.attr("dim");
+                    if (dims.n_elem == 1)
+                    {
+                        out.set_size(n);
+                    }
+                    else if (dims.n_elem == 2)
+                    {
+                        out.set_size(dims(0), dims(1));
+                    }
+                    else if (dims.n_elem == 3)
+                    {
+                        out.set_size(dims(0), dims(1), dims(2));
+                    }
+                }
+            # endif
+            for (size_t i = 0; i < n; i++)
+            {
+                out(i) = as<T>(data[i]);
             }
             return out ;
         }

inst/include/RcppArmadilloConfig.h

@@ -135,5 +135,14 @@
 //#define RCPP_ARMADILLO_RETURN_ROWVEC_AS_VECTOR
 //#define RCPP_ARMADILLO_RETURN_ANYVEC_AS_VECTOR
 
+// To preserve all dims of arma::field when passing to R the following macro 
+// can be defined before including RcppArmadillo.h. 
+// see https://github.com/RcppCore/RcppArmadillo/pull/352
+// #define RCPP_ARMADILLO_FIX_FieldImporter
+
+// To preserve all dims of and arma::field input argument when passing to C++
+// the following macro can be defined before including RcppArmadillo.h.
+// see https://github.com/RcppCore/RcppArmadillo/pull/352
+// #define RCPP_ARMADILLO_FIX_FieldExporter
 
 #endif

inst/include/RcppArmadilloWrap.h

@@ -149,7 +149,11 @@ namespace Rcpp{
     template <typename T>
     SEXP wrap( const arma::field<T>& data){
         RObject x = wrap( RcppArmadillo::FieldImporter<T>( data ) ) ;
-        x.attr("dim" ) = Dimension( data.n_rows, data.n_cols ) ;
+        # if defined(RCPP_ARMADILLO_FIX_FieldImporter)
+            x.attr("dim" ) = Dimension( data.n_rows, data.n_cols, data.n_slices ) ;
+        #else 
+            x.attr("dim" ) = Dimension( data.n_rows, data.n_cols ) ;
+        #endif
         return x ;
     }
 

inst/tinytest/test_rcpparmadillo.R

@@ -37,6 +37,7 @@ expect_equal( res[[2]][[2]], matrix(0, ncol = 5, nrow=1))#, msg = "zeros<fmat>(5
 expect_equal( res[[3]][[1]], matrix(0, ncol = 1, nrow=5))#, msg = "zeros<mat>(1,5)" )
 expect_equal( res[[3]][[2]], matrix(0, ncol = 1, nrow=5))#, msg = "zeros<mat>(1,5)" )
 
+# TODO: Revisit field tests later and fix see https://github.com/RcppCore/RcppArmadillo/pull/352
 expect_equal( res[[4]][[1]], matrix(0:3, ncol = 2, nrow=2))#, msg = "field<int>" )
 expect_equal( res[[4]][[2]], matrix(letters[1:4], ncol = 2, nrow=2))#, msg = "field<std::string>" )
 

src/RcppExports.cpp

@@ -6,6 +6,11 @@
 
 using namespace Rcpp;
 
+#ifdef RCPP_USE_GLOBAL_ROSTREAM
+Rcpp::Rostream<true>&  Rcpp::Rcout = Rcpp::Rcpp_cout_get();
+Rcpp::Rostream<false>& Rcpp::Rcerr = Rcpp::Rcpp_cerr_get();
+#endif
+
 // armadillo_version
 Rcpp::IntegerVector armadillo_version(bool single);
 RcppExport SEXP _RcppArmadillo_armadillo_version(SEXP singleSEXP) {