Hi Baptiste, On 31 May 2015 at 20:47, Baptiste Auguie wrote: | Dear list, | | My cda package (https://github.com/baptiste/cda) solves a linear system Ax=b | with Armadillo; win-builder and CRAN complain about a missing "zgels_" when | trying to build on windows or mac, as it's not part of the subset of LAPACK | provided by R libraries (I asked about this in 2011). I have included a copy of
Right. When no system lapack/blas is found, R uses its own. Which is a subset. We were bitten that once and now check in configure for availability of zgesdd. I suppose this case is similar. Look at the logic in https://github.com/RcppCore/RcppArmadillo/blob/master/configure You may need to do something similar for zgels. So this part of the problem ("do we have zgels ?") really may be part of "which type of R installation do we have". Worst case we need new branching / #ifdef logic --- but right now I think maybe more at the level of your package then at RcppArmadillo. | this file (zgels.f) from Netlib for the past few years just to make the problem | go away, but I've recently realised that zgels is not supposed to be called! It | builds fine on Linux, or any machine with a full LAPACK installed, but I'm now | wondering if solve() always calls zgels (that would be inefficient for my | use-case). >From the top-level, when I just use ag (a fantastic and much faster grep alternative; and mail will drop the ansi code for colour highlihting from the console) edd@max:~/git/rcpparmadillo(master)$ ag zgels inst/include/armadillo_bits/lapack_bones.hpp 97: #define arma_zgels zgels 205: #define arma_zgels ZGELS 340: void arma_fortran(arma_zgels)(char* trans, blas_int* m, blas_int* n, blas_int* nrhs, void* a, blas_int* lda, void* b, blas_int* ldb, void* work, blas_int* lwork, blas_int* info); inst/include/armadillo_bits/lapack_wrapper.hpp 689: arma_fortran(arma_zgels)(trans, m, n, nrhs, (T*)a, lda, (T*)b, ldb, (T*)work, lwork, info); edd@max:~/git/rcpparmadillo(master)$ I think you should discuss the merits of what gets called with Conrad. | The matrix A is square: the system is not under/overdetermined, and I believe | Armadillo should select LU factorisation rather than (slower) QR. Here's the It is hard to answer this in full generality --- and even harder to change an existing API. If Armadillo has been using QR here for years, we cannot really change this now on the request of a single package. | error I get from win-builder when I remove zgels.f from my cda package, | | cd.o:cd.cpp: | (.text$_ZN4arma6auxlib8solve_udISt7complexIdENS_3MatIS3_EEEEbRNS4_IT_EES8_RKNS_4BaseIS6_T0_EE | [bool arma::auxlib::solve_ud<std::complex<double>, arma::Mat<std::complex | <double> > >(arma::Mat<std::complex<double> >&, arma::Mat<std::complex<double> | >&, arma::Base<std::complex<double>, arma::Mat<std::complex<double> > > const | &)]+0x3a5): undefined reference to `zgels_' | | So it thinks it should call solve_ud, which is meant for under-determined | systems. Why would that be? | I tried to find the relevant piece in the template code, this looks relevant | but I don't understand it: https://github.com/RcppCore/RcppArmadillo/blob/ | master/inst/include/armadillo_bits/glue_solve_meat.hpp#L26 Well that seems to be the call in the 'rows < cols' case. But if there is a function solve_ud, can you not just call solve_ud from your package? I haven't had coffee yet so I may not need the full picture. Cheers, Dirk | | Best regards, | | baptiste | _______________________________________________ | Rcpp-devel mailing list | Rcpp-devel@lists.r-forge.r-project.org | https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel -- http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org _______________________________________________ Rcpp-devel mailing list Rcpp-devel@lists.r-forge.r-project.org https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
