I encountered a bug in RcppArmadillo when saving a row of a cube to a matrix. If one of the remaining dimensions is just of dimension 1, then dimensions are swapped. I'll illustrate the bug with an example
cppFunction("arma::mat test_row(arma::cube Rarray) {
arma::mat test = Rarray.row(0);
return test;
}", depends="RcppArmadillo")
Rarray1 <- array(NA, dim=c(100,1,2))
dim(test_row(Rarray1))
> 1 2
Rarray2 <- array(NA, dim=c(100,2,1))
dim(test_row(Rarray2))
> 1 2
When pulling out the first row and saving it to a matrix, dimensions are not kept in the second example, but swapped. I'll tested also whether this happens also when pulling out the first column or slice, but there everything seems fine. I'll just attach the code
cppFunction("arma::mat test_col(arma::cube Rarray) {
arma::mat test = Rarray.col(0);
return test;
}", depends="RcppArmadillo")
Rarray3 <- array(NA, dim=c(1,100,2))
dim(test_col(Rarray3))
> 1 2
Rarray4 <- array(NA, dim=c(2,100,1))
dim(test_col(Rarray4))
> 2 1
cppFunction("arma::mat test_slice(arma::cube Rarray) {
arma::mat test = Rarray.slice(0);
return test;
}", depends="RcppArmadillo")
Rarray5 <- array(NA, dim=c(1,2,100))
dim(test_slice(Rarray5))
> 1 2
Rarray6 <- array(NA, dim=c(2,1,100))
dim(test_slice(Rarray6))
> 2 1
I encountered a bug in RcppArmadillo when saving a row of a cube to a matrix. If one of the remaining dimensions is just of dimension 1, then dimensions are swapped. I'll illustrate the bug with an example
When pulling out the first row and saving it to a matrix, dimensions are not kept in the second example, but swapped. I'll tested also whether this happens also when pulling out the first column or slice, but there everything seems fine. I'll just attach the code