Matthias, The scalapack default 'make' includes all the lib targets, so they were built with my last compilation. Also, I ran all the test that come with the build in the TESTING directory and they passed just fine. I believe the problem is that when linking in the arch-file I'm not including a necessary library. Right now my arch file has LIBS = -lscalapack $(BLACSLIB)/blacs_MPI-LINUX-0.a $(BLACSLIB)/blacsCinit_MPI-LINUX-0.a $(BLACSLIB)/blacsF77init_MPI-LINUX-0.a $(BLACSLIB)/blacs_MPI-LINUX-0.a -llapack -lcblas -lf77blas - latlas -lblas -lg2c -lguide -lmpi -lfftw3 I thought that adding -lg2c would clear up the problem, but scalapack is making reference to things like: dlaset_ dlacpy_ zlacgv_ zlaset_ zlacpy_ dlamch_ dlapy2_ etc. I can't seem to find the library that defines those, but including whichever library it is will probably clear up the problem. So it's either linking to one more library, or a more fundamental problem with the build of one of the components (blacs, atlas, scalapack?) that I can't diagnose on my own. ~Eric Shamay <div>On 6/2/07, Matthias Krack <<a href="mailto:kr...@phys.chem.ethz.ch" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">kr...@phys.chem.ethz.ch </a>> wrote:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Eric, does your ScaLAPACK build include the toolslib? I always use the lib target lib: toolslib pblaslib redistlib scalapacklib in the ScaLAPACK makefile for the library build. Matthias </blockquote></div>