<div dir="ltr">This looks like error from ParMETIS -- some processes do not have initial vertices. <div><br></div><div>Which version of PerMETIS are you using?</div><div><br></div><div>There may be error in the way you run the test:</div><div><span style="font-size:12.800000190734863px">$ mpiexec -n 8 ./dtest input matrices/U.dat</span></div><div><span style="font-size:12.800000190734863px">Try to remove "input" in the command line.</span></div><div><span style="font-size:12.800000190734863px"><br></span></div><div><span style="font-size:12.800000190734863px">Can also try using smaller number of processes, e.g.:</span></div><div><span style="font-size:12.800000190734863px">$ mpiexec -n 2 ./dtest matrices/U.dat</span></div><div><span style="font-size:12.800000190734863px"><br></span></div><div><span style="font-size:12.800000190734863px"><br></span></div><div><span style="font-size:12.800000190734863px">Sherry Li</span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Sep 15, 2017 at 5:01 AM, Matthew Knepley <span dir="ltr"><<a href="mailto:knepley@gmail.com" target="_blank">knepley@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><span class="">On Fri, Sep 15, 2017 at 7:00 AM, Afrah Najib <span dir="ltr"><<a href="mailto:afrah.nacib@gmail.com" target="_blank">afrah.nacib@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi,<div>I am trying to run the examples of PDSLin 2.0.0[<a href="http://portal.nersc.gov/project/sparse/pdslin/" target="_blank">http://portal.nersc.gov/<wbr>project/sparse/pdslin/</a>]</div><div><br></div><div>but I got the following error:</div></div></blockquote><div><br></div></span><div>This is not a PETSc error. PETSc is just catching the signal. I think you have to contact</div><div>the PDSLin developers.</div><div><br></div><div> Thanks,</div><div><br></div><div> Matt</div><div><div class="h5"><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div>:~/pdslin_2.0.0/examples$ mpiexec -n 8 ./dtest input matrices/U.dat</div><div> input->num_doms = 4</div><div>Preconditioner parameters:</div><div> input->nproc_dcomp = 4</div><div> input->nproc_schur = 4</div><div> input->free_local = PDSLin_NO</div><div> input->dcomp_type = SCOTCH</div><div> input->diag_tau = 0.000000e+00</div><div> input->tau_sub = 0.000000e+00</div><div> input->drop_tau0 = 1.000000e-02</div><div> input->drop_tau2 = 0.000000e+00</div><div> input->drop_tau1 = 1.000000e-03</div><div> input->drop_tau3 = 0.000000e+00</div><div> input->ilu_lvl = -1</div><div> input->equil_dom = 0 (no equil or row perm).</div><div> input->perm_dom = 0</div><div> input->mat_type = UNSYMMETRIC</div><div> input->mat_pattern = UNSYMMETRIC</div><div> input->blk_size = 1</div><div> input->equil_schur = 5</div><div> input->relax_factor = 3.000000e-01</div><div> input->pperm_schur = PDSLin_YES</div><div> input->psymb_schur = PDSLin_YES</div><div> input->dom_solver = SLU_DIST</div><div>Schur solution parameters:</div><div> input->inner_outer = PDSLin_NO</div><div> input->outer_tol = 1.000000e-12</div><div> input->outer_max = 50</div><div> input->schur_itrs = PDSLin_NO</div><div> input->exact_schur = PDSLin_NO</div><div> input->direct_schur = PDSLin_NO</div><div> input->explicit_restart = PDSLin_NO</div><div> input->inner_max = 500</div><div> input->inner_restart = 60</div><div> input->inner_tol = 1.000000e-12</div><div> input->inner_solver = PDSLin_FGMRES</div><div>==== dtest(): reading in matrix from matrices/U.dat</div><div> took 1.785858e-01 seconds to read matrix.</div><div><br></div><div>******************************<wbr>******************************<wbr>**********</div><div><br></div><div><br></div><div>==== dtest: factorizing the matrix.</div><div>PARMETIS ERROR: Poor initial vertex distribution. Processor 2 has no vertices assigned to it!</div><div>PARMETIS ERROR: Poor initial vertex distribution. Processor 3 has no vertices assigned to it!</div><div>[0]PETSC ERROR: ------------------------------<wbr>------------------------------<wbr>------------</div><div>[0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range</div><div>[0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger</div><div>[0]PETSC ERROR: or see <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html#valgrind</a></div><div>[0]PETSC ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a> on GNU/linux and Apple Mac OS X to find memory corruption errors</div><div>[0]PETSC ERROR: likely location of problem given in stack below</div><div>[0]PETSC ERROR: --------------------- Stack Frames ------------------------------<wbr>------</div><div>[0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,</div><div>[0]PETSC ERROR: INSTEAD the line number of the start of the function</div><div>[0]PETSC ERROR: is given.</div><div>[0]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--</div><div>[0]PETSC ERROR: Signal received</div><div>[0]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.</div><div>[0]PETSC ERROR: Petsc Release Version 3.7.6, Apr, 24, 2017 </div><div>[0]PETSC ERROR: ./dtest on a arch-linux2-c-debug named afrah-pc by afrah Fri Sep 15 13:53:42 2017</div><div>[0]PETSC ERROR: Configure options PETSC_DIR=/home/afrah/PETSc-li<wbr>brary2/petsc-3.7.6 PETSC_ARCH=arch-linux2-c-debug prefix=/home/afrah/PETSc-libra<wbr>ry2/petsc-3.7.6/source --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 --download-blacs --download-scalapack=1 --download-mumps=1 --with-valgrind=1 --with-valgrind-dir="[/usr/loc<wbr>al/bin]"</div><div>[0]PETSC ERROR: #1 User provided function() line 0 in unknown file</div><div>application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0</div><div>[1]PETSC ERROR: ------------------------------<wbr>------------------------------<wbr>------------</div><div>[1]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range</div><div>[1]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger</div><div>[1]PETSC ERROR: or see <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html#valgrind</a></div><div>[1]PETSC ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a> on GNU/linux and Apple Mac OS X to find memory corruption errors</div><div>[1]PETSC ERROR: likely location of problem given in stack below</div><div>[1]PETSC ERROR: --------------------- Stack Frames ------------------------------<wbr>------</div><div>[1]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,</div><div>[1]PETSC ERROR: INSTEAD the line number of the start of the function</div><div>[1]PETSC ERROR: is given.</div><div>[1]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--</div><div>[1]PETSC ERROR: Signal received</div><div>[1]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.</div><div>[1]PETSC ERROR: Petsc Release Version 3.7.6, Apr, 24, 2017 </div><div>[1]PETSC ERROR: ./dtest on a arch-linux2-c-debug named afrah-pc by afrah Fri Sep 15 13:53:42 2017</div><div>[1]PETSC ERROR: Configure options PETSC_DIR=/home/afrah/PETSc-li<wbr>brary2/petsc-3.7.6 PETSC_ARCH=arch-linux2-c-debug prefix=/home/afrah/PETSc-libra<wbr>ry2/petsc-3.7.6/source --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 --download-blacs --download-scalapack=1 --download-mumps=1 --with-valgrind=1 --with-valgrind-dir="[/usr/loc<wbr>al/bin]"</div><div>[1]PETSC ERROR: #1 User provided function() line 0 in unknown file</div><div>application called MPI_Abort(MPI_COMM_WORLD, 59) - process 1</div><div>[2]PETSC ERROR: ------------------------------<wbr>------------------------------<wbr>------------</div><div>[2]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range</div><div>[2]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger</div><div>[2]PETSC ERROR: or see <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html#valgrind</a></div><div>[2]PETSC ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a> on GNU/linux and Apple Mac OS X to find memory corruption errors</div><div>[2]PETSC ERROR: likely location of problem given in stack below</div><div>[2]PETSC ERROR: --------------------- Stack Frames ------------------------------<wbr>------</div><div>[2]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,</div><div>[2]PETSC ERROR: INSTEAD the line number of the start of the function</div><div>[2]PETSC ERROR: is given.</div><div>[2]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--</div><div>[2]PETSC ERROR: Signal received</div><div>[2]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.</div><div>[2]PETSC ERROR: Petsc Release Version 3.7.6, Apr, 24, 2017 </div><div>[2]PETSC ERROR: ./dtest on a arch-linux2-c-debug named afrah-pc by afrah Fri Sep 15 13:53:42 2017</div><div>[2]PETSC ERROR: Configure options PETSC_DIR=/home/afrah/PETSc-li<wbr>brary2/petsc-3.7.6 PETSC_ARCH=arch-linux2-c-debug prefix=/home/afrah/PETSc-libra<wbr>ry2/petsc-3.7.6/source --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 --download-blacs --download-scalapack=1 --download-mumps=1 --with-valgrind=1 --with-valgrind-dir="[/usr/loc<wbr>al/bin]"</div><div>[2]PETSC ERROR: #1 User provided function() line 0 in unknown file</div><div>application called MPI_Abort(MPI_COMM_WORLD, 59) - process 2</div><div>[3]PETSC ERROR: ------------------------------<wbr>------------------------------<wbr>------------</div><div>[3]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range</div><div>[3]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger</div><div>[3]PETSC ERROR: or see <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html#valgrind</a></div><div>[3]PETSC ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a> on GNU/linux and Apple Mac OS X to find memory corruption errors</div><div>[3]PETSC ERROR: likely location of problem given in stack below</div><div>[3]PETSC ERROR: --------------------- Stack Frames ------------------------------<wbr>------</div><div>[3]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,</div><div>[3]PETSC ERROR: INSTEAD the line number of the start of the function</div><div>[3]PETSC ERROR: is given.</div><div>[3]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--</div><div>[3]PETSC ERROR: Signal received</div><div>[3]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.</div><div>[3]PETSC ERROR: Petsc Release Version 3.7.6, Apr, 24, 2017 </div><div>[3]PETSC ERROR: ./dtest on a arch-linux2-c-debug named afrah-pc by afrah Fri Sep 15 13:53:42 2017</div><div>[3]PETSC ERROR: Configure options PETSC_DIR=/home/afrah/PETSc-li<wbr>brary2/petsc-3.7.6 PETSC_ARCH=arch-linux2-c-debug prefix=/home/afrah/PETSc-libra<wbr>ry2/petsc-3.7.6/source --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 --download-blacs --download-scalapack=1 --download-mumps=1 --with-valgrind=1 --with-valgrind-dir="[/usr/loc<wbr>al/bin]"</div><div>[3]PETSC ERROR: #1 User provided function() line 0 in unknown file</div><div>application called MPI_Abort(MPI_COMM_WORLD, 59) - process 3</div><div>[4]PETSC ERROR: ------------------------------<wbr>------------------------------<wbr>------------</div><div>[4]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range</div><div>[4]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger</div><div>[4]PETSC ERROR: or see <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html#valgrind</a></div><div>[4]PETSC ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a> on GNU/linux and Apple Mac OS X to find memory corruption errors</div><div>[4]PETSC ERROR: likely location of problem given in stack below</div><div>[4]PETSC ERROR: --------------------- Stack Frames ------------------------------<wbr>------</div><div>[4]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,</div><div>[4]PETSC ERROR: INSTEAD the line number of the start of the function</div><div>[4]PETSC ERROR: is given.</div><div>[4]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--</div><div>[4]PETSC ERROR: Signal received</div><div>[4]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.</div><div>[4]PETSC ERROR: Petsc Release Version 3.7.6, Apr, 24, 2017 </div><div>[4]PETSC ERROR: ./dtest on a arch-linux2-c-debug named afrah-pc by afrah Fri Sep 15 13:53:42 2017</div><div>[4]PETSC ERROR: Configure options PETSC_DIR=/home/afrah/PETSc-li<wbr>brary2/petsc-3.7.6 PETSC_ARCH=arch-linux2-c-debug prefix=/home/afrah/PETSc-libra<wbr>ry2/petsc-3.7.6/source --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 --download-blacs --download-scalapack=1 --download-mumps=1 --with-valgrind=1 --with-valgrind-dir="[/usr/loc<wbr>al/bin]"</div><div>[4]PETSC ERROR: #1 User provided function() line 0 in unknown file</div><div>application called MPI_Abort(MPI_COMM_WORLD, 59) - process 4</div><div>[5]PETSC ERROR: ------------------------------<wbr>------------------------------<wbr>------------</div><div>[5]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range</div><div>[5]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger</div><div>[5]PETSC ERROR: or see <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html#valgrind</a></div><div>[5]PETSC ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a> on GNU/linux and Apple Mac OS X to find memory corruption errors</div><div>[5]PETSC ERROR: likely location of problem given in stack below</div><div>[5]PETSC ERROR: --------------------- Stack Frames ------------------------------<wbr>------</div><div>[5]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,</div><div>[5]PETSC ERROR: INSTEAD the line number of the start of the function</div><div>[5]PETSC ERROR: is given.</div><div>[5]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--</div><div>[5]PETSC ERROR: Signal received</div><div>[5]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.</div><div>[5]PETSC ERROR: Petsc Release Version 3.7.6, Apr, 24, 2017 </div><div>[5]PETSC ERROR: ./dtest on a arch-linux2-c-debug named afrah-pc by afrah Fri Sep 15 13:53:42 2017</div><div>[5]PETSC ERROR: Configure options PETSC_DIR=/home/afrah/PETSc-li<wbr>brary2/petsc-3.7.6 PETSC_ARCH=arch-linux2-c-debug prefix=/home/afrah/PETSc-libra<wbr>ry2/petsc-3.7.6/source --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 --download-blacs --download-scalapack=1 --download-mumps=1 --with-valgrind=1 --with-valgrind-dir="[/usr/loc<wbr>al/bin]"</div><div>[5]PETSC ERROR: #1 User provided function() line 0 in unknown file</div><div>application called MPI_Abort(MPI_COMM_WORLD, 59) - process 5</div><div>[6]PETSC ERROR: [7]PETSC ERROR: ------------------------------<wbr>------------------------------<wbr>------------</div><div>[7]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range</div><div>[7]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger</div><div>[7]PETSC ERROR: or see <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html#valgrind</a></div><div>[7]PETSC ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a> on GNU/linux and Apple Mac OS X to find memory corruption errors</div><div>[7]PETSC ERROR: likely location of problem given in stack below</div><div>[7]PETSC ERROR: --------------------- Stack Frames ------------------------------<wbr>------</div><div>[7]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,</div><div>[7]PETSC ERROR: INSTEAD the line number of the start of the function</div><div>[7]PETSC ERROR: is given.</div><div>[7]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--</div><div>[7]PETSC ERROR: Signal received</div><div>[7]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.</div><div>[7]PETSC ERROR: Petsc Release Version 3.7.6, Apr, 24, 2017 </div><div>[7]PETSC ERROR: ./dtest on a arch-linux2-c-debug named afrah-pc by afrah Fri Sep 15 13:53:42 2017</div><div>[7]PETSC ERROR: Configure options PETSC_DIR=/home/afrah/PETSc-li<wbr>brary2/petsc-3.7.6 PETSC_ARCH=arch-linux2-c-debug prefix=/home/afrah/PETSc-libra<wbr>ry2/petsc-3.7.6/source --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 --download-blacs --download-scalapack=1 --download-mumps=1 --with-valgrind=1 --with-valgrind-dir="[/usr/loc<wbr>al/bin]"</div><div>[7]PETSC ERROR: #1 User provided function() line 0 in unknown file</div><div>application called MPI_Abort(MPI_COMM_WORLD, 59) - process 7</div><div>------------------------------<wbr>------------------------------<wbr>------------</div><div>[6]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range</div><div>[6]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger</div><div>[6]PETSC ERROR: or see <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html#valgrind</a></div><div>[6]PETSC ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a> on GNU/linux and Apple Mac OS X to find memory corruption errors</div><div>[6]PETSC ERROR: likely location of problem given in stack below</div><div>[6]PETSC ERROR: --------------------- Stack Frames ------------------------------<wbr>------</div><div>[6]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,</div><div>[6]PETSC ERROR: INSTEAD the line number of the start of the function</div><div>[6]PETSC ERROR: is given.</div><div>[6]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--</div><div>[6]PETSC ERROR: Signal received</div><div>[6]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.</div><div>[6]PETSC ERROR: Petsc Release Version 3.7.6, Apr, 24, 2017 </div><div>[6]PETSC ERROR: ./dtest on a arch-linux2-c-debug named afrah-pc by afrah Fri Sep 15 13:53:42 2017</div><div>[6]PETSC ERROR: Configure options PETSC_DIR=/home/afrah/PETSc-li<wbr>brary2/petsc-3.7.6 PETSC_ARCH=arch-linux2-c-debug prefix=/home/afrah/PETSc-libra<wbr>ry2/petsc-3.7.6/source --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 --download-blacs --download-scalapack=1 --download-mumps=1 --with-valgrind=1 --with-valgrind-dir="[/usr/loc<wbr>al/bin]"</div><div>[6]PETSC ERROR: #1 User provided function() line 0 in unknown file</div><div>application called MPI_Abort(MPI_COMM_WORLD, 59) - process 6</div></div><div><br></div><div>any idea</div></div>
</blockquote></div></div></div><span class="HOEnZb"><font color="#888888"><br><br clear="all"><div><br></div>-- <br><div class="m_600396375239683464gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener</div><div><br></div><div><a href="http://www.caam.rice.edu/~mk51/" target="_blank">http://www.caam.rice.edu/~<wbr>mk51/</a><br></div></div></div>
</font></span></div></div>
</blockquote></div><br></div>