GeezerVison

Hello sommer team,

Eigen 5.0.0, which we are trying to bring to CRAN in an updated RcppEigen, did away with Eigen::MappedSparseMatrix. (Also note that they changed the versioning scheme so Eigen 5.0.0 corresponds to 3.5.0 under the old scheme.) See RcppEigen issue 151 for all the changes related to this upgrade.

For MappedSparseMatrix, a change to Map works -- which was done in a good handful of places. No other changes are made in the PR. As with the other packages, this permits compilation under existing (Rcpp)Eigen and the candidate release permitting the upgrade. Because I generally run a newer Rcpp here and didn't want anything to spill I edited RcppExports.cpp rather than regenerate it. You may to want to overwrite this with a newly generated one, the effect ought to be identical.

So if you could apply this PR and get the update to CRAN before we update, a new RcppEigen would not break your package. If you don't update it we would get breakage 😞 but this PR overcomes this. We have been at this update for a long time as there were other issues in affected packages so the upload is not really imminent -- but getting closer, and we are now looking at mid-to-late November. If you can get this to CRAN over the next few weeks we would appreciate it. 'Some time' in the near future will work, you can see at RcppEigen issue 151 how the other changes come in.

Thanks!