<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; color: rgb(0, 0, 0); font-size: 14px; font-family: Calibri, sans-serif; "><div>Hi all. I recently needed to use a LAPACK routine in a Cactus thorn. Since my local machine's installation of LAPACK & BLAS was old, I decided to force an installation by including the thorns "ExternalLibraries/[BLAS,LAPACK]". This seemed to work, with the resulting .a files ending up in configs/<my config name>/scratch/external/LAPACK, etc. Compiling and running my cactus executable, however, I found the LAPACK gave completely wrong results. </div><div><br></div><div>For a much simpler test case that (see attached F90 standalone program), consider the 2x2 system A x = b, where A = (3, 2\\2, 6), and b = (5, 8).</div><div><br></div><div>Correct result for "x" is (1,1).</div><div><br></div><div>Cactus-forced LAPACK (using routine "dgesv") yields (-2,1).</div><div><br></div><div>I later installed LAPACK (v. 3.3.0) + BLAS by hand on my machine. Linking against these yields the correct answer.</div><div><br></div><div>I'm on a 32-bit Linux machine, using the Intel 10 compilers.</div><div><br></div><div>I'd appreciate any insights on this. Thanks,</div><div><br></div><div>Bernard</div></body></html>