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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Map dgCmatrix as integer sparse matrix","articleBody":"Dear developers,\r\n\r\nI have a dgCmatrix in R and want to call a function as below in cpp to deal with it. \r\n\r\nEigen::SparseMatrix\u003cdouble\u003e calc_overlap(Eigen::Map\u003cEigen::SparseMatrix\\\u003cint\\\u003e\u003e\u0026 cc_adj,\r\n                                         Eigen::Map\u003cEigen::SparseMatrix\\\u003cint\\\u003e\u003e\u0026 cg_adj,\r\n                                        double threshold) {\r\n         Eigen::SparseMatrix\\\u003cint\\\u003e overlap_mat_all = cc_adj * cg_adj;\r\n         return overlap_mat_all;\r\n}\r\n\r\nThe dgCmatrix 'cc_adj' and 'cg_adj' in R are large sparse matrices with integer values. I want to calculate the product of them by cpp.  I used  'Map' to get rid of deep copies of these two large matrices. The scalar \\\u003cint\\\u003e is used to save memory. There is no error raised up when mapping to a dgCmatrix with \\\u003cint\\\u003e. but I'm not sure how it's working exactly. I guess the function makes deep copies instead, so the mapping doesn't work at all. Is it right?\r\n\r\nMy concern is that since you only allow mapping to dgCmatrix format sparse matrix for now,  is there any possibility that you could wrap up a function to deal with 'ngCmatrix'?\r\n\r\nLooking forward to your kind reply.\r\n","author":{"url":"https://github.com/yanzhaobiomath","@type":"Person","name":"yanzhaobiomath"},"datePublished":"2023-10-19T13:53:20.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/132/RcppEigen/issues/132"}