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Description
Problem: update matrix passed by reference from R
Code:
Rcpp::cppFunction(" void test_arma(arma::mat& A) { A.fill(1); return; }", depends="RcppArmadillo") Rcpp::cppFunction(" void test_eigen(Eigen::Map<Eigen::MatrixXd> A) { A.fill(1); return; }", depends="RcppEigen") Rcpp::cppFunction(" void test_rcpp(Rcpp::NumericMatrix A) { A.fill(1); return; }") f<-function(M=1e6, N=1e4, init="array", test="arma") { if (init=="array") { A<-array(0, c(M, N)) } else { A<-matrix(0, nrow=M, ncol=N) } label<- paste0("start, ", init, ", ", test) before<- paste0("A[1, 1] = ", A[1, 1], ", A[M, N] = ", A[M, N]) x<-A[M, N] if (test=="arma") { test_arma(A) } elseif (test=="rcpp") { test_rcpp(A) } elseif (test=="eigen") { test_eigen(A) } after<- paste0("A[1, 1] = ", A[1, 1], ", A[M, N] = ", A[M, N]) y<-A[M, N] worked<- c("worked", "not worked")[1+ as.integer(x==y)] message(paste0(label, " before ", before, " after ", after, "", worked)) } for (initin c("array", "matrix")) { for (testin c("arma", "rcpp", "eigen")) { system.time(f(M=1e6, N=1e4, init=init, test=test)) gc() } }Results and Sessioninfo:
Reproducible conda env:
mamba create -n r44 r-base=4.4.0 r-rcpp=1.0.13 r-rcpparmadillo r-rcppeigenBtw, with Rcpp=1.0.12, the above code reported:
start, array, arma before A[1, 1] = 0, A[M, N] = 0 after A[1, 1] = 1, A[M, N] = 0 not worked start, array, rcpp before A[1, 1] = 0, A[M, N] = 0 after A[1, 1] = 1, A[M, N] = 1 worked start, array, eigen before A[1, 1] = 0, A[M, N] = 0 after A[1, 1] = 1, A[M, N] = 1 worked start, matrix, arma before A[1, 1] = 0, A[M, N] = 0 after A[1, 1] = 1, A[M, N] = 0 not worked start, matrix, rcpp before A[1, 1] = 0, A[M, N] = 0 after A[1, 1] = 1, A[M, N] = 1 worked start, matrix, eigen before A[1, 1] = 0, A[M, N] = 0 after A[1, 1] = 1, A[M, N] = 1 worked > sessionInfo() R version 4.4.0 (2024-04-24) Platform: x86_64-pc-linux-gnu Running under: Ubuntu 22.04.4 LTS Matrix products: default BLAS: /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3 LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.20.so; LAPACK version 3.10.0 locale: [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8 LC_MONETARY=en_US.UTF-8 [6] LC_MESSAGES=en_US.UTF-8 LC_PAPER=en_US.UTF-8 LC_NAME=C LC_ADDRESS=C LC_TELEPHONE=C [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C time zone: Europe/Copenhagen tzcode source: system (glibc) attached base packages: [1] stats graphics grDevices utils datasets methods base loaded via a namespace (and not attached): [1] compiler_4.4.0 RcppEigen_0.3.4.0.0 tools_4.4.0 RcppArmadillo_0.12.8.4.0 Rcpp_1.0.12 Metadata
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