]> Hello Stephane (and the rest of the ocaml community)--- Thank you for your input here. I do have libgfortran.a, but I might note that it's in /usr/lib/gcc/i486-linux-gnu/4.3/ rather than /usr/lib. This is in contrast to liblapack.a, etc, which just live in /usr/lib. This makes me wonder if this is somehow the problem. I did try (naievely!) copying libgfortran.a over to /usr/lib. I also added /usr/lib/gcc/i486-linux-gnu/4.3/ to my list of directories. No luck yet. Also $ ldd /usr/lib/liblapack.so linux-gate.so.1 => (0xffffe000) libblas.so.3gf => /usr/lib/libblas.so.3gf (0xb775d000) libgfortran.so.3 => /usr/lib/libgfortran.so.3 (0xb76ab000) libm.so.6 => /lib/i686/cmov/libm.so.6 (0xb7684000) libgcc_s.so.1 => /lib/libgcc_s.so.1 (0xb7677000) libc.so.6 => /lib/i686/cmov/libc.so.6 (0xb751c000) /lib/ld-linux.so.2 (0x80000000) $ locate linux-gate.a $ locate libblas.a /usr/lib/libblas.a $ locate libgfortran.a /usr/lib/gcc/i486-linux-gnu/4.3/libgfortran.a $ locate libm.a /usr/lib/libm.a /usr/lib/xen/libm.a $ locate libgcc_s.a $ locate libc.a /usr/lib/libc.a /usr/lib/xen/libc.a So everything there seems to be OK. Also # ldd /usr/lib/gcc/i486-linux-gnu/4.3/libgfortran.so linux-gate.so.1 => (0xffffe000) libm.so.6 => /lib/i686/cmov/libm.so.6 (0xb7ed9000) libc.so.6 => /lib/i686/cmov/libc.so.6 (0xb7d7e000) /lib/ld-linux.so.2 (0x80000000) Here is my compile line ocamlopt \ # source directories: -I /home/matsen/ocaml/bio/ -I /home/matsen/ocaml/common/ -I /usr/lib/ocaml/3.10.2/pcre/ -I /usr/lib/ocaml/3.10.2/glpk/ -I /usr/lib/ocaml/3.10.2/gsl/ -I /usr/lib/ocaml/3.10.2/lacaml/ -I /usr/lib/gcc/i486-linux-gnu/4.3/ \ # cc directives -ccopt -static -ccopt -lgfortran -ccopt -L/home/matsen/ocaml/bio/ -ccopt -L/home/matsen/ocaml/common/ -ccopt -L/usr/lib/ocaml/3.10.2/pcre/ -ccopt -L/usr/lib/ocaml/3.10.2/glpk/ -ccopt -L/usr/lib/ocaml/3.10.2/gsl/ -ccopt -L/usr/lib/ocaml/3.10.2/lacaml/ -ccopt -L/usr/lib/gcc/i486-linux-gnu/4.3/ pcre.cmxa bigarray.cmxa unix.cmxa gsl.cmxa lacaml.cmxa -o placer \ # my code /home/matsen/ocaml/common/common_base.cmx /home/matsen/ocaml/bio/biobase.cmx base.cmx minimization.cmx integration.cmx /home/matsen/ocaml/bio/liketree.cmx liketreeFuns.cmx /home/matsen/ocaml/common/number.cmx /home/matsen/ocaml/common/mat.cmx /home/matsen/ocaml/bio/diagd.cmx /home/matsen/ocaml/bio/qtree.cmx /home/matsen/ocaml/bio/protModels.cmx /home/matsen/ocaml/bio/alignment.cmx /home/matsen/ocaml/bio/alignmentLike.cmx placerFuns.cmx placer.cmx Thank you again for your help. If we can get this running, I'll definitely acknowledge your help in our paper, which is in the long run about understanding the distribution of phytoplankton in the ocean and ramifications for carbon cycling (very relevant for climate change...). Erick