Package: r-cran-gnm Version: 1.1-1-2 Severity: serious Tags: sid bookworm X-Debbugs-CC: debian-ci@lists.debian.org User: debian-ci@lists.debian.org Usertags: needs-update Dear Maintainer, Since the upload of lapack 3.10.0-1, the autopkgtest of r-cran-gnm fails in unstable. See for example: https://ci.debian.net/data/autopkgtest/unstable/amd64/r/r-cran-gnm/15155026/log.gz More precisely, test-biplot.R fails, because some results have the opposite sign compared to the one which is expected. My understanding is that this comes from the SVD of barleyMatrix in that test file, which is different between lapack 3.9 and 3.10. Mathematically, the SVD is not unique, and lapack 3.10 returns a different (still valid) solution. More precisely, I verified that one of the right-singular vector of that matrix has the opposite sign in lapack 3.10. I also verified that the decomposition is correct by checking that: max(abs(barleySVD$u %*% diag(barleySVD$d) %*% t(barleySVD$v) - barleyMatrix)) is a small value (about 2e-14). Also note that the hardcoded expected values already partially differ from those of the original research paper mentioned in that test (Gabriel (1998): Generalised bilinear regression). More precisely, half of the values were hardcoded with the opposite sign. It seems that now all values need to be hardcoded with the opposite sign. The testsuite of r-cran-gnm thus needs to be adapted, by being more tolerant to such sign changes. N.B. : when trying to reproduce the problem, please ensure that your lapack alternative (as given by “update-alternatives --display liblapack.so.3-x86_64-linux-gnu) points to /usr/lib/x86_64-linux- gnu/lapack/liblapack.so.3, and not to the binary provided by either openblas or atlas (because these two have not yet been recompiled against lapack 3.10, and thus do not expose the problem). Best regards, -- ⢀⣴⠾⠻⢶⣦⠀ Sébastien Villemot ⣾⠁⢠⠒⠀⣿⡁ Debian Developer ⢿⡄⠘⠷⠚⠋⠀ https://sebastien.villemot.name ⠈⠳⣄⠀⠀⠀⠀ https://www.debian.org
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