Thanks Yixuan, I expected this was the case but thought it was worth
asking. It really seems a shame to me that R doesn't have float arrays.
In the mean time I guess I will need to have the functions create copies.
Regards,
Charles
On Thu, Jun 25, 2015 at 12:28 AM, Yixuan Qiu <yixuan....@cos.name> wrote:
> Hi Charles,
> The Map class is designed to reuse the memory allocated by some other
> program such as R, and due to this reason the memory layout must be
> consistent with the declared matrix type. In R there is no such float
> arrays, so there is no way to directly map it to a MatrixXf object. I
> suppose you can make a copy of the source matrix and cast it to float type
> using the cast() method.
>
>
> Best,
> Yixuan
>
> 2015-06-25 3:31 GMT+08:00 Charles Determan <cdeterma...@gmail.com>:
>
>> I have been exploring the use of RcppEigen more recently and stumbled
>> upon an issue when passing R objects. Is there a way to pass an R matrix
>> and get it in to a mapped Eigen MatrixXf object? I know R doesn't have a
>> native float type so I am not overly surprised that I have run in to this
>> issue.
>>
>> For example, the following works simply when expecting a double matrix.
>>
>> #include <RcppEigen.h>
>>
>> // [[Rcpp::depends(RcppEigen)]]
>>
>> using Eigen::Map;
>> using Eigen::MatrixXd;
>>
>> // [[Rcpp::export]]
>> void floatMatrix(Map<MatrixXd> M){
>> std::cout << M << std::endl;
>> }
>>
>> However, when I try to change MatrixXd to MatrixXf the compilation fails
>> stating:
>>
>> no matching function for call to 'eigen::Map<Eigen::Matrix<float, -1,
>> -1> ::Map(Rcpp::Vector<14, Rcpp::PreserveStorage>::iterator, int&, int&)'
>>
>> I tried searching around online if I could downcast the Mapped MatrixXd
>> but I have been unsuccessful. Any insights would be appreciated.
>>
>> Regards,
>> Charles
>>
>> _______________________________________________
>> Rcpp-devel mailing list
>> Rcpp-devel@lists.r-forge.r-project.org
>> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
>>
>
>
>
> --
> Yixuan Qiu <yixuan....@cos.name>
> Department of Statistics,
> Purdue University
>
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