Spencer, I wanted to verify that I have properly installed R. I was not specifically looking for long double.
Thanks, Naresh Sent from my iPhone > On Oct 23, 2025, at 7:40 PM, Spencer Graves <[email protected]> > wrote: > > Naresh: > > > May I ask the application that requires long.double? > > > Might it make sense to revise the algorithm of the application to get > enhanced precision without long.doubles? > > > EXAMPLE: Ordinary least squares regression to estimate b in Y = X b + e as > b-hat = inverse(X'X) = X'Y. However, computing it that way discards half of > the precision. To see that, we write X as its singular value decomposition > UDV'. Then X'X = V D^2 V' and X'Y = V D Y. Then inverse(X'X) = inverse(V') > inverse(D)^-2 inverse(V) %*% V D U' Y. If you compute that way, you throw > away half of the precision of D. You can avoid that by computing inverse(V') > inverse(D) U' Y. > > > This computation is more commonly done using the QR decomposition, where the > loss of numeric precision is equivalent but not as obvious. > > > ??? > Please excuse if I have once again exposed my infinite ignorance. Spencer > Graves > > >> On 10/23/25 17:27, Simon Urbanek wrote: >> Naresh, >> Both of those can only be FALSE by definition: >> 1) arm64 hardware (Apple Silicon, i.e M1,2,3,4) has no support for long >> doubles, so you cannot enable that one. >> 2) libxml is always FALSE since 4.2.0 - see ?capabilities: >> libxml: is there support for integrating ‘libxml’ with the R event loop? >> ‘TRUE’ as from R 3.3.0, ‘FALSE’ as from R 4.2.0. >> Cheers, >> Simon >> PS: what you described in "My installation was in two steps” has no effect >> on R or its capabilities. Those steps are only required if you want to >> compile R yourself (or re-compile some packages). >>>> On 24/10/2025, at 10:35 AM, Naresh Gurbuxani >>>> <[email protected]> wrote: >>> >>> On my new macbook pro, I installed R using package installer >>> R-4.5.1-arm64.pkg >>> My installation lacks long.double and libxml capabilities. How can these >>> be enabled? >>> >>> My installation was in two steps: >>> 1. Install Xcode developer tools (sudo xcode-select install), GNU fortran >>> compiler (gfortran-14.2-universal.pkg at cran), gnu readline, liblzma, and >>> pcre2 (using macports), texlive, and Xquartz. Install R using above >>> package installer. >>> 2. Source install.R from https://mac.r-project.org/bin/. In sudo R >>> session, run install.libs("r-base-dev"). Reinstall R using above package >>> installer. >>> >>>> capabilities() >>> jpeg png tiff tcltk X11 aqua >>> TRUE TRUE TRUE TRUE TRUE TRUE >>> http/ftp sockets libxml fifo cledit iconv >>> TRUE TRUE FALSE TRUE TRUE TRUE >>> NLS Rprof profmem cairo ICU long.double >>> TRUE TRUE TRUE TRUE TRUE FALSE >>> libcurl >>> TRUE >>>> sessionInfo() >>> R version 4.5.1 (2025-06-13) >>> Platform: aarch64-apple-darwin20 >>> Running under: macOS Sequoia 15.4.1 >>> >>> Matrix products: default >>> BLAS: >>> /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libRblas.0.dylib >>> LAPACK: >>> /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libRlapack.dylib; >>> LAPACK version 3.12.1 >>> >>> locale: >>> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8 >>> >>> time zone: America/New_York >>> tzcode source: internal >>> >>> attached base packages: >>> [1] stats graphics utils datasets grDevices methods base >>> >>> other attached packages: >>> [1] latticeExtra_0.6-31 lattice_0.22-7 colorspace_2.1-2 >>> >>> loaded via a namespace (and not attached): >>> [1] compiler_4.5.1 deldir_2.0-4 RColorBrewer_1.1-3 Rcpp_1.1.0 >>> [5] interp_1.1-6 jpeg_0.1-11 grid_4.5.1 png_0.1-8 >>>> >>> >>> nareshgurbuxani$ gfortran --version >>> GNU Fortran (GCC) 14.2.0 >>> Copyright (C) 2024 Free Software Foundation, Inc. >>> This is free software; see the source for copying conditions. There is NO >>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. >>> >>> [[alternative HTML version deleted]] >>> >>> _______________________________________________ >>> R-SIG-Mac mailing list >>> [email protected] >>> https://stat.ethz.ch/mailman/listinfo/r-sig-mac >>> >> _______________________________________________ >> R-SIG-Mac mailing list >> [email protected] >> https://stat.ethz.ch/mailman/listinfo/r-sig-mac > _______________________________________________ R-SIG-Mac mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-mac
